Merge bitcoin/bitcoin#21239: guix: Add codesignature attachment support for osx+win

ee88320 guix: repro: Sort find output in libtool for gcc-8 (Carl Dong)
ee0a67c codesigning: Use SHA256 as digest for osslsigncode (Windows) (Carl Dong)
38eb91e guix: Add codesigning functionality (Carl Dong)
bac2690 guix: Package codesigning tools (Carl Dong)
0a2176d guix: Reindent existing manifest.scm (Carl Dong)
c090a3e Makefile.am: use APP_DIST_DIR instead of hard-coding dist (Carl Dong)

Pull request description:

  This is the last PR before we reach feature-parity with the Gitian process!

  Note: I tried using the `Makefile` inside the distsrc to make the dmg instead of manually listing out the commands, but `make` seems to want to re-make a lot of other files which broke the dmg.

  The workflow looks something like this:
  1. `env [ FOO=bar... ] ./contrib/guix/guix-build` (add additional env vars as necessary)
  2. Codesigners only:
      1.  Copy `guix-build-<short-id>/output/x86_64-apple-darwin18/bitcoin-<short-id>-osx-unsigned.tar.gz` and `guix-build-<short-id>/output/x86_64-w64-mingw32/bitcoin-<short-id>-win-unsigned.tar.gz` to signing computer
      2. Codesign with `./detached-sig-create.sh` inside the tarball
      3. Upload contents of `signature-{osx,win}.tar.gz` to https://github.com/bitcoin-core/bitcoin-detached-sigs (as a new tag)
  3. Checkout new tag for `bitcoin-core/bitcoin-detached-sigs` with the detached signatures
  4. `env [ FOO=bar... ] DETACHED_SIGS_REPO=<path/to/bitcoin-detached-sigs> ./contrib/guix/guix-codesign` (modify env vars as necessary)
  5. Make sure `guix.sigs` is cloned and updated
  6. `env GUIX_SIGS_REPO=<path/to/guix.sigs> SIGNER=0x96AB007F1A7ED999=dongcarl ./contrib/guix/guix-attest` (modify env vars as necessary)
  7. Commit your new signatures and SHA256SUMS in `guix.sigs`
  8. Optionally, after there are multiple signatures in `guix.sigs`: `env GUIX_SIGS_REPO=<path/to/guix.sigs> ./contrib/guix/guix-verify`

ACKs for top commit:
  laanwj:
    Tested ACK ee88320
  achow101:
    ACK ee88320

Tree-SHA512: e812a07a5f19f900600c70cb9c717769ef544a6c0c12760b5558b76b6b37df863257f3dbf38b0757e6e06e334470267e94c9f2bdbc27409d6837b1a0bfc6acbc

Author: laanwj

Makefile.am

@@ -149,7 +149,7 @@ $(APP_DIST_DIR)/Applications:
 $(APP_DIST_EXTRAS): $(APP_DIST_DIR)/$(OSX_APP)/Contents/MacOS/Bitcoin-Qt
 
 $(OSX_TEMP_ISO): $(APP_DIST_EXTRAS)
-	$(XORRISOFS) -D -l -V "$(OSX_VOLNAME)" -no-pad -r -dir-mode 0755 -o $@ dist -- $(if $(SOURCE_DATE_EPOCH),-volume_date all_file_dates =$(SOURCE_DATE_EPOCH))
+	$(XORRISOFS) -D -l -V "$(OSX_VOLNAME)" -no-pad -r -dir-mode 0755 -o $@ $(APP_DIST_DIR) -- $(if $(SOURCE_DATE_EPOCH),-volume_date all_file_dates =$(SOURCE_DATE_EPOCH))
 
 $(OSX_DMG): $(OSX_TEMP_ISO)
 	$(DMG) dmg "$<" "$@"

contrib/guix/guix-build

@@ -267,20 +267,20 @@ for host in $HOSTS; do
     make -C "${PWD}/depends" -j"$JOBS" download-"$(host_to_commonname "$host")" ${V:+V=1} ${SOURCES_PATH:+SOURCES_PATH="$SOURCES_PATH"}
 done
 
-# Usage: outdir_for_host HOST
+# Usage: outdir_for_host HOST SUFFIX
 #
 #   HOST: The current platform triple we're building for
 #
 outdir_for_host() {
-    echo "${OUTDIR_BASE}/${1}"
+    echo "${OUTDIR_BASE}/${1}${2:+-${2}}"
 }
 
-# Usage: profiledir_for_host HOST COMMAND
+# Usage: profiledir_for_host HOST SUFFIX
 #
 #   HOST: The current platform triple we're building for
 #
 profiledir_for_host() {
-    echo "${PROFILES_BASE}/${2}-${1}"
+    echo "${PROFILES_BASE}/${1}${2:+-${2}}"
 }
 
 
@@ -412,7 +412,7 @@ EOF
                                  --keep-failed \
                                  --fallback \
                                  --link-profile \
-                                 --root="$(profiledir_for_host "${HOST}" build)" \
+                                 --root="$(profiledir_for_host "${HOST}")" \
                                  ${SUBSTITUTE_URLS:+--substitute-urls="$SUBSTITUTE_URLS"} \
                                  ${ADDITIONAL_GUIX_COMMON_FLAGS} ${ADDITIONAL_GUIX_ENVIRONMENT_FLAGS} \
                                  -- env HOST="$host" \