From 30cea4875fc38803872d995d3ace1e9b4aa7aa63 Mon Sep 17 00:00:00 2001
From: lufia <lufia@lufia.org>
Date: Mon, 19 Aug 2019 13:26:53 +0900
Subject: [PATCH 1/3] Change HOME, PATH, and .gitconfig paths to be
 customizable

In Plan 9, almost environment variables are not capitalized.

Signed-off-by: lufia <lufia@lufia.org>
---
 Makefile           | 40 +++++++++++++++++++++++++++++++++++++---
 builtin/config.c   |  2 +-
 config.c           |  2 +-
 credential-cache.c |  2 +-
 credential-store.c |  2 +-
 exec-cmd.c         |  4 ++--
 git-compat-util.h  |  8 ++++++++
 help.c             |  2 +-
 path.c             |  6 +++---
 run-command.c      |  4 ++--
 sequencer.c        |  2 +-
 shell.c            |  2 +-
 12 files changed, 59 insertions(+), 17 deletions(-)

diff --git a/Makefile b/Makefile
index 90aa329eb78368..95bf9bdb25c6bb 100644
--- a/Makefile
+++ b/Makefile
@@ -525,8 +525,21 @@ perllibdir = $(sharedir)/perl5
 localedir = $(sharedir)/locale
 template_dir = share/git-core/templates
 htmldir = $(prefix)/share/doc/git-doc
-ETC_GITCONFIG = $(sysconfdir)/gitconfig
-ETC_GITATTRIBUTES = $(sysconfdir)/gitattributes
+ifndef ETC_GITCONFIG
+	ETC_GITCONFIG = $(sysconfdir)/gitconfig
+endif
+ifndef ETC_GITATTRIBUTES
+	ETC_GITATTRIBUTES = $(sysconfdir)/gitattributes
+endif
+ifndef USER_GITCONFIG
+	USER_GITCONFIG = ~/.gitconfig
+endif
+ifndef USER_GITCREDENTIALS
+	USER_GITCREDENTIALS = ~/.git-credentials
+endif
+ifndef USER_GITCREDENTIAL_CACHE
+	USER_GITCREDENTIAL_CACHE = ~/.git-credential-cache
+endif
 lib = lib
 # DESTDIR =
 pathsep = :
@@ -1930,6 +1943,9 @@ endif
 
 ETC_GITCONFIG_SQ = $(subst ','\'',$(ETC_GITCONFIG))
 ETC_GITATTRIBUTES_SQ = $(subst ','\'',$(ETC_GITATTRIBUTES))
+USER_GITCONFIG_SQ = $(subst ','\'',$(USER_GITCONFIG))
+USER_GITCREDENTIALS_SQ = $(subst ','\'',$(USER_GITCREDENTIALS))
+USER_GITCREDENTIAL_CACHE_SQ = $(subst ','\'',$(USER_GITCREDENTIAL_CACHE))
 
 DESTDIR_SQ = $(subst ','\'',$(DESTDIR))
 bindir_SQ = $(subst ','\'',$(bindir))
@@ -2426,12 +2442,30 @@ builtin/init-db.sp builtin/init-db.s builtin/init-db.o: EXTRA_CPPFLAGS = \
 
 config.sp config.s config.o: GIT-PREFIX
 config.sp config.s config.o: EXTRA_CPPFLAGS = \
-	-DETC_GITCONFIG='"$(ETC_GITCONFIG_SQ)"'
+	-DETC_GITCONFIG='"$(ETC_GITCONFIG_SQ)"' \
+	-DUSER_GITCONFIG='"$(USER_GITCONFIG_SQ)"'
+
+builtin/config.sp builtin/config.s builtin/config.o: GIT-PREFIX
+builtin/config.sp builtin/config.s builtin/config.o: EXTRA_CPPFLAGS = \
+	-DUSER_GITCONFIG='"$(USER_GITCONFIG_SQ)"'
+
+sequencer.sp sequencer.s sequencer.o: GIT-PREFIX
+sequencer.sp sequencer.s sequencer.o: EXTRA_CPPFLAGS = \
+	-DUSER_GITCONFIG='"$(USER_GITCONFIG_SQ)"'
 
 attr.sp attr.s attr.o: GIT-PREFIX
 attr.sp attr.s attr.o: EXTRA_CPPFLAGS = \
 	-DETC_GITATTRIBUTES='"$(ETC_GITATTRIBUTES_SQ)"'
 
+credential-cache.sp credential-cache.s credential-cache.o: GIT-PREFIX
+credential-cache.sp credential-cache.s credential-cache.o: EXTRA_CPPFLAGS = \
+	-DUSER_GITCONFIG='"$(USER_GITCONFIG_SQ)"' \
+	-DUSER_GITCREDENTIAL_CACHE='"$(USER_GITCREDENTIAL_CACHE_SQ)"'
+
+credential-store.sp credential-store.s credential-store.o: GIT-PREFIX
+credential-store.sp credential-store.s credential-store.o: EXTRA_CPPFLAGS = \
+	-DUSER_GITCREDENTIALS='"$(USER_GITCREDENTIALS_SQ)"'
+
 gettext.sp gettext.s gettext.o: GIT-PREFIX
 gettext.sp gettext.s gettext.o: EXTRA_CPPFLAGS = \
 	-DGIT_LOCALE_PATH='"$(localedir_relative_SQ)"'
diff --git a/builtin/config.c b/builtin/config.c
index ee4aef6a355576..90434bbdd57988 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -642,7 +642,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 	}
 
 	if (use_global_config) {
-		char *user_config = expand_user_path("~/.gitconfig", 0);
+		char *user_config = expand_user_path(USER_GITCONFIG, 0);
 		char *xdg_config = xdg_config_home("config");
 
 		if (!user_config)
diff --git a/config.c b/config.c
index 8db9c77098f01b..ba46bced671c23 100644
--- a/config.c
+++ b/config.c
@@ -1716,7 +1716,7 @@ static int do_git_config_sequence(const struct config_options *opts,
 {
 	int ret = 0;
 	char *xdg_config = xdg_config_home("config");
-	char *user_config = expand_user_path("~/.gitconfig", 0);
+	char *user_config = expand_user_path(USER_GITCONFIG, 0);
 	char *repo_config;
 	enum config_scope prev_parsing_scope = current_parsing_scope;
 
diff --git a/credential-cache.c b/credential-cache.c
index 1cccc3a0b9cfb2..3e2ed6c0bed251 100644
--- a/credential-cache.c
+++ b/credential-cache.c
@@ -87,7 +87,7 @@ static char *get_socket_path(void)
 {
 	struct stat sb;
 	char *old_dir, *socket;
-	old_dir = expand_user_path("~/.git-credential-cache", 0);
+	old_dir = expand_user_path(USER_GITCREDENTIAL_CACHE, 0);
 	if (old_dir && !stat(old_dir, &sb) && S_ISDIR(sb.st_mode))
 		socket = xstrfmt("%s/socket", old_dir);
 	else
diff --git a/credential-store.c b/credential-store.c
index 294e7716815622..7d236a3129ee1f 100644
--- a/credential-store.c
+++ b/credential-store.c
@@ -169,7 +169,7 @@ int cmd_main(int argc, const char **argv)
 	if (file) {
 		string_list_append(&fns, file);
 	} else {
-		if ((file = expand_user_path("~/.git-credentials", 0)))
+		if ((file = expand_user_path(USER_GITCREDENTIALS, 0)))
 			string_list_append_nodup(&fns, file);
 		file = xdg_config_home("credentials");
 		if (file)
diff --git a/exec-cmd.c b/exec-cmd.c
index 7deeab30397cf2..c95fc8dbdd81a3 100644
--- a/exec-cmd.c
+++ b/exec-cmd.c
@@ -304,7 +304,7 @@ static void add_path(struct strbuf *out, const char *path)
 void setup_path(void)
 {
 	const char *exec_path = git_exec_path();
-	const char *old_path = getenv("PATH");
+	const char *old_path = getenv(PATH_ENVIRONMENT);
 	struct strbuf new_path = STRBUF_INIT;
 
 	git_set_exec_path(exec_path);
@@ -315,7 +315,7 @@ void setup_path(void)
 	else
 		strbuf_addstr(&new_path, _PATH_DEFPATH);
 
-	setenv("PATH", new_path.buf, 1);
+	setenv(PATH_ENVIRONMENT, new_path.buf, 1);
 
 	strbuf_release(&new_path);
 }
diff --git a/git-compat-util.h b/git-compat-util.h
index a73632e8e43ce9..9f0856e1c53b78 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -1224,6 +1224,14 @@ int warn_on_fopen_errors(const char *path);
 # define SHELL_PATH "/bin/sh"
 #endif
 
+#ifndef HOME_ENVIRONMENT
+# define HOME_ENVIRONMENT "HOME"
+#endif
+
+#ifndef PATH_ENVIRONMENT
+# define PATH_ENVIRONMENT "PATH"
+#endif
+
 #ifndef _POSIX_THREAD_SAFE_FUNCTIONS
 #define flockfile(fh)
 #define funlockfile(fh)
diff --git a/help.c b/help.c
index 1de9c0d589cd9b..3b29a1c89a8c73 100644
--- a/help.c
+++ b/help.c
@@ -260,7 +260,7 @@ void load_command_list(const char *prefix,
 		struct cmdnames *main_cmds,
 		struct cmdnames *other_cmds)
 {
-	const char *env_path = getenv("PATH");
+	const char *env_path = getenv(PATH_ENVIRONMENT);
 	const char *exec_path = git_exec_path();
 
 	if (exec_path) {
diff --git a/path.c b/path.c
index 8b2c7531919eef..1cca180767bcd5 100644
--- a/path.c
+++ b/path.c
@@ -737,7 +737,7 @@ char *expand_user_path(const char *path, int real_home)
 		const char *username = path + 1;
 		size_t username_len = first_slash - username;
 		if (username_len == 0) {
-			const char *home = getenv("HOME");
+			const char *home = getenv(HOME_ENVIRONMENT);
 			if (!home)
 				goto return_null;
 			if (real_home)
@@ -1507,7 +1507,7 @@ char *xdg_config_home(const char *filename)
 	if (config_home && *config_home)
 		return mkpathdup("%s/git/%s", config_home, filename);
 
-	home = getenv("HOME");
+	home = getenv(HOME_ENVIRONMENT);
 	if (home)
 		return mkpathdup("%s/.config/git/%s", home, filename);
 	return NULL;
@@ -1522,7 +1522,7 @@ char *xdg_cache_home(const char *filename)
 	if (cache_home && *cache_home)
 		return mkpathdup("%s/git/%s", cache_home, filename);
 
-	home = getenv("HOME");
+	home = getenv(HOME_ENVIRONMENT);
 	if (home)
 		return mkpathdup("%s/.cache/git/%s", home, filename);
 	return NULL;
diff --git a/run-command.c b/run-command.c
index 9b3a57d1e392c8..7ddf5ad4f0a198 100644
--- a/run-command.c
+++ b/run-command.c
@@ -180,14 +180,14 @@ int is_executable(const char *name)
  */
 static char *locate_in_PATH(const char *file)
 {
-	const char *p = getenv("PATH");
+	const char *p = getenv(PATH_ENVIRONMENT);
 	struct strbuf buf = STRBUF_INIT;
 
 	if (!p || !*p)
 		return NULL;
 
 	while (1) {
-		const char *end = strchrnul(p, ':');
+		const char *end = strchrnul(p, PATH_SEP);
 
 		strbuf_reset(&buf);
 
diff --git a/sequencer.c b/sequencer.c
index fd7701c88a8643..a40dc85d4dc468 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1170,7 +1170,7 @@ N_("Your name and email address were configured automatically based\n"
 
 static const char *implicit_ident_advice(void)
 {
-	char *user_config = expand_user_path("~/.gitconfig", 0);
+	char *user_config = expand_user_path(USER_GITCONFIG, 0);
 	char *xdg_config = xdg_config_home("config");
 	int config_exists = file_exists(user_config) || file_exists(xdg_config);
 
diff --git a/shell.c b/shell.c
index cef7ffdc9e1d30..06c69411c38046 100644
--- a/shell.c
+++ b/shell.c
@@ -40,7 +40,7 @@ static char *make_cmd(const char *prog)
 
 static void cd_to_homedir(void)
 {
-	const char *home = getenv("HOME");
+	const char *home = getenv(HOME_ENVIRONMENT);
 	if (!home)
 		die("could not determine user's home directory; HOME is unset");
 	if (chdir(home) == -1)

From 8aadd6444dfafe554d452555d42e7dd885d7155e Mon Sep 17 00:00:00 2001
From: lufia <lufia@lufia.org>
Date: Mon, 19 Aug 2019 13:29:44 +0900
Subject: [PATCH 2/3] Fix C syntactic errors for the Plan 9 C compiler

Signed-off-by: lufia <lufia@lufia.org>
---
 compat/plan9/openssl/crypto.h |  5 +++++
 compat/regex/regex_internal.h |  3 +++
 config.c                      |  3 ++-
 git-compat-util.h             |  9 ++++++++-
 parse-options.h               |  9 +++++++++
 remove-bitfields.sh           | 17 +++++++++++++++++
 6 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 compat/plan9/openssl/crypto.h
 create mode 100755 remove-bitfields.sh

diff --git a/compat/plan9/openssl/crypto.h b/compat/plan9/openssl/crypto.h
new file mode 100644
index 00000000000000..9d1ef43422ce19
--- /dev/null
+++ b/compat/plan9/openssl/crypto.h
@@ -0,0 +1,5 @@
+#ifndef __attribute__
+#define __attribute__(x)
+#endif
+
+#include_next <openssl/crypto.h>
diff --git a/compat/regex/regex_internal.h b/compat/regex/regex_internal.h
index 0bad8b841eda89..dd17948e4e4a8f 100644
--- a/compat/regex/regex_internal.h
+++ b/compat/regex/regex_internal.h
@@ -25,6 +25,9 @@
 #include <stdio.h>
 #include <string.h>
 
+#ifdef NEEDS_SYS_PARAM_H
+#include <sys/param.h>
+#endif
 #if defined HAVE_LANGINFO_H || defined HAVE_LANGINFO_CODESET || defined _LIBC
 # include <langinfo.h>
 #endif
diff --git a/config.c b/config.c
index ba46bced671c23..6b3057e9cd1014 100644
--- a/config.c
+++ b/config.c
@@ -2457,7 +2457,8 @@ static int store_aux_event(enum config_event_t type,
 			return error(_("invalid section name '%s'"), cf->var.buf);
 
 		if (cf->subsection_case_sensitive)
-			cmpfn = strncasecmp;
+			/* Plan 9's strncasecmp is typed (char*, char*, int) */
+			cmpfn = (int (*)(const char*, const char*, size_t))strncasecmp;
 		else
 			cmpfn = strncmp;
 
diff --git a/git-compat-util.h b/git-compat-util.h
index 9f0856e1c53b78..2d977cde0bd563 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -164,7 +164,11 @@
 #define GIT_WINDOWS_NATIVE
 #endif
 
+#include <sys/types.h>
 #include <unistd.h>
+#ifdef __PLAN9__
+#include <libv.h>
+#endif
 #include <stdio.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -180,7 +184,6 @@
 #ifdef NEEDS_SYS_PARAM_H
 #include <sys/param.h>
 #endif
-#include <sys/types.h>
 #include <dirent.h>
 #include <sys/time.h>
 #include <time.h>
@@ -282,6 +285,10 @@ char *gitbasename(char *);
 char *gitdirname(char *);
 #endif
 
+#ifdef __PLAN9__
+#include <machine/endian.h>
+#endif
+
 #ifndef NO_ICONV
 #include <iconv.h>
 #endif
diff --git a/parse-options.h b/parse-options.h
index 46af9420930552..6e932ab0a5511e 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -59,6 +59,15 @@ enum parse_opt_result {
 	PARSE_OPT_UNKNOWN
 };
 
+enum parse_opt_result {
+	PARSE_OPT_COMPLETE = -3,
+	PARSE_OPT_HELP = -2,
+	PARSE_OPT_ERROR = -1,	/* must be the same as error() */
+	PARSE_OPT_DONE = 0,	/* fixed so that "return 0" works */
+	PARSE_OPT_NON_OPTION,
+	PARSE_OPT_UNKNOWN
+};
+
 struct option;
 typedef int parse_opt_cb(const struct option *, const char *arg, int unset);
 
diff --git a/remove-bitfields.sh b/remove-bitfields.sh
new file mode 100755
index 00000000000000..952bd34f124e62
--- /dev/null
+++ b/remove-bitfields.sh
@@ -0,0 +1,17 @@
+#!/bin/ape/sh
+# Plan 9 C compiler rejects initialization a structure including bit field.
+# usage: remove-bitfields.sh [dir ...]
+
+if ! echo abc | sed 's/(ab)c/\1/' >/dev/null 2>&1
+then
+	alias sed='sed -E'
+fi
+
+trap 'rm -f /tmp/remove-bitfields.$pid; exit 1' 1 2 3 15 EXIT
+
+files=$(du -a $* | awk '/\.[ch]$/ { print $2 }')
+for i in $files
+do
+	sed '/(^[ 	]*\*|\?)/!s/([a-z]+[a-z0-9]*) *: *[0-9]+([,;])/\1\2/g' $i >/tmp/remove-bitfields.$pid
+	cp /tmp/remove-bitfields.$pid $i
+done

From 8d54009a44c9e660bf29b3053b8d9bf1b78e2871 Mon Sep 17 00:00:00 2001
From: lufia <lufia@lufia.org>
Date: Sat, 24 Aug 2019 12:15:03 +0900
Subject: [PATCH 3/3] Support Plan 9 dialect

Plan 9 ANSI/POSIX environment is:
* No expr(1)
* sed(1) limits max length of label to 7 characters
* pcc ignores object files that has incorrect extension,
  so should use underlying loader directly.
* No ln(1). Instead use bind(1), but bind isn't persisted to the disk.
  However it isn't efficient to copy git to git subcommands such as git-add.
  Therefore Plan 9 needs exec-wrapper to switch behavior by executable name.
* tar(1) don't have -o option

Signed-off-by: lufia <lufia@lufia.org>
---
 GIT-VERSION-GEN     |  2 +-
 Makefile            | 41 ++++++++++++++-----
 config.mak.uname    | 99 +++++++++++++++++++++++++++++++++++++++++++++
 exec-wrapper.c      | 16 ++++++++
 generate-cmdlist.sh | 24 ++++++++---
 t/chainlint.sed     | 66 +++++++++++++++---------------
 templates/Makefile  | 12 +++++-
 7 files changed, 208 insertions(+), 52 deletions(-)
 create mode 100644 exec-wrapper.c

diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index c30d71abda0b3d..e8b3c250e911b5 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -26,7 +26,7 @@ else
 	VN="$DEF_VER"
 fi
 
-VN=$(expr "$VN" : v*'\(.*\)')
+VN=${VN#v}
 
 if test -r $GVF
 then
diff --git a/Makefile b/Makefile
index 95bf9bdb25c6bb..36cfbda647e3bf 100644
--- a/Makefile
+++ b/Makefile
@@ -556,6 +556,7 @@ export prefix bindir sharedir sysconfdir gitwebdir perllibdir localedir
 
 # Set our default programs
 CC = cc
+LD = cc
 AR = ar
 RM = rm -f
 DIFF = diff
@@ -792,6 +793,10 @@ ALL_PROGRAMS = $(PROGRAMS) $(SCRIPTS)
 # what 'all' will build but not install in gitexecdir
 OTHER_PROGRAMS = git$X
 
+# what 'all' will build but not install in neither bindir and gitexecdir,
+COMPAT_PROGRAM_OBJS =
+COMPAT_PROGRAMS =
+
 # what test wrappers are needed and 'install' will install, in bindir
 BINDIR_PROGRAMS_NEED_X += git
 BINDIR_PROGRAMS_NEED_X += git-receive-pack
@@ -1882,6 +1887,11 @@ ifndef PAGER_ENV
 PAGER_ENV = LESS=FRX LV=-c
 endif
 
+ifdef USE_EXEC_WRAPPER
+	COMPAT_PROGRAM_OBJS += exec-wrapper.o
+	COMPAT_PROGRAMS += exec-wrapper$X
+endif
+
 QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
 QUIET_SUBDIR1  =
 
@@ -2082,7 +2092,7 @@ profile-fast: profile-clean
 	$(MAKE) PROFILE=USE all
 
 
-all:: $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) $(OTHER_PROGRAMS) GIT-BUILD-OPTIONS
+all:: $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) $(OTHER_PROGRAMS) $(COMPAT_PROGRAMS) GIT-BUILD-OPTIONS
 ifneq (,$X)
 	$(QUIET_BUILT_IN)$(foreach p,$(patsubst %$X,%,$(filter %$X,$(ALL_PROGRAMS) $(BUILT_INS) git$X)), test -d '$p' -o '$p' -ef '$p$X' || $(RM) '$p';)
 endif
@@ -2142,7 +2152,7 @@ git.sp git.s git.o: EXTRA_CPPFLAGS = \
 	'-DGIT_INFO_PATH="$(infodir_relative_SQ)"'
 
 git$X: git.o GIT-LDFLAGS $(BUILTIN_OBJS) $(GITLIBS)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) \
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) \
 		$(filter %.o,$^) $(LIBS)
 
 help.sp help.s help.o: command-list.h
@@ -2161,10 +2171,11 @@ version.sp version.s version.o: EXTRA_CPPFLAGS = \
 		GIT_CEILING_DIRECTORIES="$(CURDIR)/.." \
 		git rev-parse -q --verify HEAD 2>/dev/null)"'
 
-$(BUILT_INS): git$X
+$(BUILT_INS): git$X $(COMPAT_PROGRAMS)
 	$(QUIET_BUILT_IN)$(RM) $@ && \
 	ln $< $@ 2>/dev/null || \
 	ln -s $< $@ 2>/dev/null || \
+	cp exec-wrapper$X $@ 2>/dev/null || \
 	cp $< $@
 
 config-list.h: generate-configlist.sh
@@ -2370,6 +2381,7 @@ VCSSVN_OBJS += vcs-svn/svndump.o
 
 TEST_OBJS := $(patsubst %$X,%.o,$(TEST_PROGRAMS)) $(patsubst %,t/helper/%,$(TEST_BUILTINS_OBJS))
 OBJECTS := $(LIB_OBJS) $(BUILTIN_OBJS) $(PROGRAM_OBJS) $(TEST_OBJS) \
+	$(COMPAT_PROGRAM_OBJS) \
 	$(XDIFF_OBJS) \
 	$(VCSSVN_OBJS) \
 	$(FUZZ_OBJS) \
@@ -2490,26 +2502,33 @@ compat/nedmalloc/nedmalloc.sp compat/nedmalloc/nedmalloc.o: EXTRA_CPPFLAGS = \
 compat/nedmalloc/nedmalloc.sp: SP_EXTRA_FLAGS += -Wno-non-pointer-null
 endif
 
+exec-wrapper.sp exec-wrapper.s exec-wrapper.o: EXTRA_CPPFLAGS = \
+	'-DGIT_EXEC_PATH="$(gitexecdir_SQ)"' \
+	'-DBINDIR="$(bindir_relative_SQ)"'
+
+exec-wrapper$X: exec-wrapper.o GIT-LDFLAGS
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^)
+
 git-%$X: %.o GIT-LDFLAGS $(GITLIBS)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS)
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS)
 
 git-bugreport$X: bugreport.o GIT-LDFLAGS $(GITLIBS)
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
 		$(LIBS)
 
 git-imap-send$X: imap-send.o $(IMAP_SEND_BUILDDEPS) GIT-LDFLAGS $(GITLIBS)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
 		$(IMAP_SEND_LDFLAGS) $(LIBS)
 
 git-http-fetch$X: http.o http-walker.o http-fetch.o GIT-LDFLAGS $(GITLIBS)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
 		$(CURL_LIBCURL) $(LIBS)
 git-http-push$X: http.o http-push.o GIT-LDFLAGS $(GITLIBS)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
 		$(CURL_LIBCURL) $(EXPAT_LIBEXPAT) $(LIBS)
 
 git-remote-testsvn$X: remote-testsvn.o GIT-LDFLAGS $(GITLIBS) $(VCSSVN_LIB)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS) \
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS) \
 	$(VCSSVN_LIB)
 
 $(REMOTE_CURL_ALIASES): $(REMOTE_CURL_PRIMARY)
@@ -2519,7 +2538,7 @@ $(REMOTE_CURL_ALIASES): $(REMOTE_CURL_PRIMARY)
 	cp $< $@
 
 $(REMOTE_CURL_PRIMARY): remote-curl.o http.o http-walker.o GIT-LDFLAGS $(GITLIBS)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) \
 		$(CURL_LIBCURL) $(EXPAT_LIBEXPAT) $(LIBS)
 
 $(LIB_FILE): $(LIB_OBJS)
@@ -2814,7 +2833,7 @@ t/helper/test-svn-fe$X: $(VCSSVN_LIB)
 t/helper/test-tool$X: $(patsubst %,t/helper/%,$(TEST_BUILTINS_OBJS))
 
 t/helper/test-%$X: t/helper/test-%.o GIT-LDFLAGS $(GITLIBS)
-	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(filter %.a,$^) $(LIBS)
+	$(QUIET_LINK)$(LD) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(filter %.a,$^) $(LIBS)
 
 check-sha1:: t/helper/test-tool$X
 	t/helper/test-sha1.sh
@@ -2997,6 +3016,7 @@ endif
 		{ test -z "$(NO_INSTALL_HARDLINKS)" && \
 		  ln "$$bindir/git$X" "$$bindir/$$p" 2>/dev/null || \
 		  ln -s "git$X" "$$bindir/$$p" 2>/dev/null || \
+		  cp "exec-wrapper$X" "$$execdir/$$p" 2>/dev/null || \
 		  cp "$$bindir/git$X" "$$bindir/$$p" || exit; } \
 	done && \
 	for p in $(BUILT_INS); do \
@@ -3006,6 +3026,7 @@ endif
 		{ test -z "$(NO_INSTALL_HARDLINKS)" && \
 		  ln "$$execdir/git$X" "$$execdir/$$p" 2>/dev/null || \
 		  ln -s "git$X" "$$execdir/$$p" 2>/dev/null || \
+		  cp "exec-wrapper$X" "$$execdir/$$p" 2>/dev/null || \
 		  cp "$$execdir/git$X" "$$execdir/$$p" || exit; } \
 	done && \
 	remote_curl_aliases="$(REMOTE_CURL_ALIASES)" && \
diff --git a/config.mak.uname b/config.mak.uname
index c7eba69e54e669..e176b74db12753 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -436,6 +436,7 @@ ifeq ($(uname_S),Windows)
 
 	CC = compat/vcbuild/scripts/clink.pl
 	AR = compat/vcbuild/scripts/lib.pl
+	LD = $(CC)
 	CFLAGS =
 	BASIC_CFLAGS = -nologo -I. -Icompat/vcbuild/include -DWIN32 -D_CONSOLE -DHAVE_STRING_H -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_DEPRECATE
 	COMPAT_OBJS = compat/msvc.o compat/winansi.o \
@@ -518,6 +519,7 @@ ifeq ($(uname_S),NONSTOP_KERNEL)
 	# INLINE='' would just replace one set of warnings with another and
 	# still not compile in c89 mode, due to non-const array initializations.
 	CC = cc -c99
+	LD = $(CC)
 	# Build down-rev compatible objects that don't use our new getopt_long.
 	ifeq ($(uname_R).$(uname_V),J06.21)
 		CC += -WRVU=J06.20
@@ -665,8 +667,10 @@ else
 			BASIC_LDFLAGS += -Wl,--large-address-aware
 		endif
 		CC = gcc
+		LD = $(CC)
 		COMPAT_CFLAGS += -D__USE_MINGW_ANSI_STDIO=0 -DDETECT_MSYS_TTY \
 			-fstack-protector-strong
+		BASIC_LDFLAGS += -fstack-protector-strong
 		EXTLIBS += -lntdll
 		INSTALL = /bin/install
 		NO_R_TO_GCC_LINKER = YesPlease
@@ -699,6 +703,101 @@ ifeq ($(uname_S),QNX)
 	NO_STRCASESTR = YesPlease
 	NO_STRLCPY = YesPlease
 endif
+ifeq ($(uname_S),Plan9)
+	CC = pcc
+	CFLAGS = -FVB+
+	ARFLAGS = uv
+	# pcc don't use mismatched objfiles
+	ifeq ($(objtype),386)
+		LD = 8l
+	endif
+	ifeq ($(objtype),amd64)
+		LD = 6l
+	endif
+	ifeq ($(objtype),arm)
+		LD = 5l
+	endif
+	ifeq ($(objtype),mips)
+		LD = vl
+	endif
+	ifeq ($(objtype),mips64)
+		LD = 4l
+	endif
+	ifeq ($(objtype),power)
+		LD = ql
+	endif
+	ifeq ($(objtype),sparc)
+		LD = kl
+	endif
+	ifeq ($(objtype),spim)
+		LD = 0l
+	endif
+	ifeq ($(objtype),spim64)
+		LD = xl
+	endif
+	BASIC_CFLAGS += -Icompat/plan9
+	BASIC_CFLAGS += -D__PLAN9__
+	BASIC_CFLAGS += -D_POSIX_SOURCE
+	BASIC_CFLAGS += -D_BSD_EXTENSION
+	BASIC_CFLAGS += -D_SUSV2_SOURCE
+	BASIC_CFLAGS += -D_PLAN9_SOURCE
+	BASIC_CFLAGS += -D_RESEARCH_SOURCE
+	BASIC_CFLAGS += -D_REENTRANT_SOURCE
+	BASIC_CFLAGS += -DHAVE_SOCK_OPTS
+	BASIC_CFLAGS += -Dsockaddr_storage=sockaddr_in6
+	BASIC_CFLAGS += -DHOME_ENVIRONMENT=\"home\"
+	BASIC_CFLAGS += -DPATH_ENVIRONMENT=\"path\"
+	BASIC_CFLAGS += -D_PATH_SEP=1
+	BASIC_CFLAGS += -D_PATH_DEFPATH=\"/bin\\x01.\\x01/bin/ape\"
+	COMPAT_CFLAGS += -DHAVE_STDINT_H
+	COMPAT_CFLAGS += -DHAVE_LOCALE_H
+	LDFLAGS = -L/$(objtype)/lib/ape
+
+	NEEDS_CRYPTO_WITH_SSL = YesPlease
+	NEEDS_SYS_PARAM_H = YesPlease
+	NO_NSEC = YesPlease
+	NO_SYMLINK_HEAD = YesPlease
+	NO_GECOS_IN_PWENT = YesPlease
+	NO_GETTEXT = YesPlease
+	NO_SETENV = YesPlease
+	NO_STRCASESTR = YesPlease
+	NO_STRLCPY = YesPlease
+	NO_STRTOUMAX = YesPlease
+	NO_REGEX = YesPlease
+	NO_MKDTEMP = YesPlease
+	NO_UNSETENV = YesPlease
+	NO_INITGROUPS = YesPlease
+	NO_MMAP = YesPlease
+	NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
+	NO_STRUCT_ITIMERVAL = YesPlease
+	NO_SETITIMER = YesPlease
+	NO_ICONV = YesPlease
+	NO_SYMLINK_HEAD = YesPlease
+	OPENSSL_SHA1 = YesPlease
+	OPENSSL_SHA256 = YesPlease
+	NO_MEMMEM = YesPlease
+	HAVE_CLOCK_GETTIME = YesPlease
+
+	NO_SVN_TESTS = YesPlease
+	NO_PERL = YesPlease
+	NO_PYTHON = YesPlease
+	NO_TCLTK = YesPlease
+	NO_INSTALL_HARDLINKS = YesPlease
+
+	ETC_GITCONFIG = /sys/lib/git/config
+	ETC_GITATTRIBUTES = /sys/lib/git/attributes
+	USER_GITCONFIG = ~/lib/git/config
+	USER_GITCREDENTIALS = ~/lib/git/credentials
+	USER_GITCREDENTIAL_CACHE = ~/lib/git/credential-cache
+
+	DEFAULT_PAGER = /bin/p
+	PAGER_ENV = terminal=
+	SHELL_PATH = /bin/ape/sh
+	DEFAULT_EDITOR = /bin/ed
+
+	CURL_LDFLAGS = -lcurl -lssl -lcrypto
+	USE_EXEC_WRAPPER = YesPlease
+endif
 
 vcxproj:
 	# Require clean work tree
diff --git a/exec-wrapper.c b/exec-wrapper.c
new file mode 100644
index 00000000000000..b56e871d029782
--- /dev/null
+++ b/exec-wrapper.c
@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(int argc, char **argv)
+{
+	/* we should detect git-core path */
+
+	USED(argc);
+	if (execv("/bin/git", argv) < 0) {
+		fprintf(stderr, "%s: %s\n", argv[0], strerror(errno));
+		return 1;
+	}
+	return 0; /* can't happen */
+}
diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
index 45fecf8bdfb21a..bb6f9d7e0b30d5 100755
--- a/generate-cmdlist.sh
+++ b/generate-cmdlist.sh
@@ -1,5 +1,10 @@
 #!/bin/sh
 
+if ! echo abc | sed 's/(ab)c/\1/' >/dev/null 2>&1
+then
+	alias sed='sed -E'
+fi
+
 die () {
 	echo "$@" >&2
 	exit 1
@@ -10,7 +15,7 @@ command_list () {
 }
 
 get_categories () {
-	tr ' ' '\n'|
+	tr ' ' '\012'|
 	grep -v '^$' |
 	sort |
 	uniq
@@ -18,16 +23,16 @@ get_categories () {
 
 category_list () {
 	command_list "$1" |
-	cut -c 40- |
+	awk '{ print substr($0, 40) }' |
 	get_categories
 }
 
 get_synopsis () {
 	sed -n '
-		/^NAME/,/'"$1"'/H
+		/^NAME/,/'"$1"'/h
 		${
 			x
-			s/.*'"$1"' - \(.*\)/N_("\1")/
+			s/.*'"$1"' - (.*)/N_("\1")/
 			p
 		}' "Documentation/$1.txt"
 }
@@ -60,16 +65,23 @@ define_category_names () {
 	echo "};"
 }
 
+if test -z "$(echo -n)"
+then
+	alias print='echo -n'
+else
+	alias print='printf %s'
+fi
+
 print_command_list () {
 	echo "static struct cmdname_help command_list[] = {"
 
 	command_list "$1" |
 	while read cmd rest
 	do
-		printf "	{ \"$cmd\", $(get_synopsis $cmd), 0"
+		print "	{ \"$cmd\", $(get_synopsis $cmd), 0"
 		for cat in $(echo "$rest" | get_categories)
 		do
-			printf " | CAT_$cat"
+			print " | CAT_$cat"
 		done
 		echo " },"
 	done
diff --git a/t/chainlint.sed b/t/chainlint.sed
index 70df40e34b7df8..7282e7b4266d2d 100644
--- a/t/chainlint.sed
+++ b/t/chainlint.sed
@@ -117,7 +117,7 @@
 /^[ 	]*!*[ 	]*(..*)[ 	]*[0-9]*[<>|&]/boneline
 
 # multi-line "(...\n...)"
-/^[ 	]*(/bsubshell
+/^[ 	]*(/bsubsh
 
 # innocuous line -- print it and advance to next line
 b
@@ -130,11 +130,11 @@ b
 }
 b
 
-:subshell
+:subsh
 # bare "(" line? -- stash for later printing
 /^[ 	]*([	]*$/ {
 	h
-	bnextline
+	bnextln
 }
 # "(..." line -- split off and stash "(", then process "..." as its own line
 x
@@ -143,7 +143,7 @@ x
 s/(//
 bslurp
 
-:nextline
+:nextln
 N
 s/.*\n//
 
@@ -151,10 +151,10 @@ s/.*\n//
 # incomplete line "...\"
 /\\$/bicmplte
 # multi-line quoted string "...\n..."?
-/"/bdqstring
+/"/bdqstr
 # multi-line quoted string '...\n...'? (but not contraction in string "it's")
 /'/{
-	/"[^'"]*'[^'"]*"/!bsqstring
+	/"[^'"]*'[^'"]*"/!bsqstr
 }
 :folded
 # here-doc -- swallow it
@@ -163,8 +163,8 @@ s/.*\n//
 # before closing ")", "done", "elsif", "else", or "fi" will need to be
 # re-visited to drop "suspect" marking since final line of those constructs
 # legitimately lacks "&&", so "suspect" mark must be removed
-/^[ 	]*#/bnextline
-/^[ 	]*$/bnextline
+/^[ 	]*#/bnextln
+/^[ 	]*$/bnextln
 # in-line comment -- strip it (but not "#" in a string, Bash ${#...} array
 # length, or Perforce "//depot/path#42" revision in filespec)
 /[ 	]#/{
@@ -175,22 +175,22 @@ s/.*\n//
 # multi-line "case ... esac"
 /^[ 	]*case[ 	]..*[ 	]in/bcase
 # multi-line "for ... done" or "while ... done"
-/^[ 	]*for[ 	]..*[ 	]in/bcontinue
-/^[ 	]*while[ 	]/bcontinue
-/^[ 	]*do[ 	]/bcontinue
-/^[ 	]*do[ 	]*$/bcontinue
-/;[ 	]*do/bcontinue
+/^[ 	]*for[ 	]..*[ 	]in/bcnt
+/^[ 	]*while[ 	]/bcnt
+/^[ 	]*do[ 	]/bcnt
+/^[ 	]*do[ 	]*$/bcnt
+/;[ 	]*do/bcnt
 /^[ 	]*done[ 	]*&&[ 	]*$/bdone
 /^[ 	]*done[ 	]*$/bdone
 /^[ 	]*done[ 	]*[<>|]/bdone
 /^[ 	]*done[ 	]*)/bdone
-/||[ 	]*exit[ 	]/bcontinue
-/||[ 	]*exit[ 	]*$/bcontinue
+/||[ 	]*exit[ 	]/bcnt
+/||[ 	]*exit[ 	]*$/bcnt
 # multi-line "if...elsif...else...fi"
-/^[ 	]*if[ 	]/bcontinue
-/^[ 	]*then[ 	]/bcontinue
-/^[ 	]*then[ 	]*$/bcontinue
-/;[ 	]*then/bcontinue
+/^[ 	]*if[ 	]/bcnt
+/^[ 	]*then[ 	]/bcnt
+/^[ 	]*then[ 	]*$/bcnt
+/;[ 	]*then/bcnt
 /^[ 	]*elif[ 	]/belse
 /^[ 	]*elif[ 	]*$/belse
 /^[ 	]*else[ 	]/belse
@@ -234,10 +234,10 @@ s/.*\n//
 	}
 }
 # line ends with pipe "...|" -- valid; not missing "&&"
-/|[ 	]*$/bcontinue
+/|[ 	]*$/bcnt
 # missing end-of-line "&&" -- mark suspect
 /&&[ 	]*$/!s/^/?!AMP?!/
-:continue
+:cnt
 # retrieve and print previous line
 x
 n
@@ -250,7 +250,7 @@ s/\\\n//
 bslurp
 
 # check for multi-line double-quoted string "...\n..." -- fold to one line
-:dqstring
+:dqstr
 # remove all quote pairs
 s/"\([^"]*\)"/@!\1@!/g
 # done if no dangling quote
@@ -258,13 +258,13 @@ s/"\([^"]*\)"/@!\1@!/g
 # otherwise, slurp next line and try again
 N
 s/\n//
-bdqstring
+bdqstr
 :dqdone
 s/@!/"/g
 bfolded
 
 # check for multi-line single-quoted string '...\n...' -- fold to one line
-:sqstring
+:sqstr
 # remove all quote pairs
 s/'\([^']*\)'/@!\1@!/g
 # done if no dangling quote
@@ -272,7 +272,7 @@ s/'\([^']*\)'/@!\1@!/g
 # otherwise, slurp next line and try again
 N
 s/\n//
-bsqstring
+bsqstr
 :sqdone
 s/@!/'/g
 bfolded
@@ -282,11 +282,11 @@ bfolded
 :heredoc
 s/^\(.*\)<<[ 	]*[-\\'"]*\([A-Za-z0-9_][A-Za-z0-9_]*\)['"]*/<\2>\1<</
 s/[ 	]*<<//
-:heredsub
+:heresub
 N
 /^<\([^>]*\)>.*\n[ 	]*\1[ 	]*$/!{
 	s/\n.*$//
-	bheredsub
+	bheresub
 }
 s/^<[^>]*>//
 s/\n.*$//
@@ -305,7 +305,7 @@ bcase
 x
 s/?!AMP?!//
 x
-bcontinue
+bcnt
 
 # found "done" closing for-loop or while-loop, or "fi" closing if-then -- drop
 # "suspect" from final contained line since that line legitimately lacks "&&"
@@ -321,10 +321,10 @@ bchkchn
 # found nested multi-line "(...\n...)" -- pass through untouched
 :nest
 x
-:nstslurp
+:nstslrp
 n
 # closing ")" on own line -- stop nested slurp
-/^[ 	]*)/bnstclose
+/^[ 	]*)/bnstclos
 # comment -- not closing ")" if in comment
 /^[ 	]*#/bnstcnt
 # "$((...))" -- arithmetic expansion; not closing ")"
@@ -332,11 +332,11 @@ n
 # "$(...)" -- command substitution; not closing ")"
 /\$([^)][^)]*)[^)]*$/bnstcnt
 # closing "...)" -- stop nested slurp
-/)/bnstclose
+/)/bnstclos
 :nstcnt
 x
-bnstslurp
-:nstclose
+bnstslrp
+:nstclos
 s/^/>>/
 # is it "))" which closes nested and parent subshells?
 /)[ 	]*)/bslurp
diff --git a/templates/Makefile b/templates/Makefile
index d22a71a3999b3d..19216a924a4f9b 100644
--- a/templates/Makefile
+++ b/templates/Makefile
@@ -4,8 +4,16 @@ ifndef V
 	QUIET = @
 endif
 
+uname_S := $(shell sh -c 'uname -s 2>/dev/null || echo not')
+
 INSTALL ?= install
 TAR ?= tar
+TAR_CF = $(TAR) cf
+TAR_XF = $(TAR) xof
+ifeq ($(uname_S),Plan9)
+	TAR_CF = $(TAR) cf
+	TAR_XF = $(TAR) xf
+endif
 RM ?= rm -f
 prefix ?= $(HOME)
 template_instdir ?= $(prefix)/share/git-core/templates
@@ -62,5 +70,5 @@ clean:
 
 install: all
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(template_instdir_SQ)'
-	(cd blt && $(TAR) cf - .) | \
-	(cd '$(DESTDIR_SQ)$(template_instdir_SQ)' && umask 022 && $(TAR) xof -)
+	(cd blt && $(TAR_CF) - .) | \
+	(cd '$(DESTDIR_SQ)$(template_instdir_SQ)' && umask 022 && $(TAR_XF) -)