installer/portable: make it easier to include tmux in custom installers

It is not necessarily obvious that `tmux.exe` is not the only needed
file, but the msys-event DLL is needed, too.

Let's just hide this option behind the environment variable
INCLUDE_TMUX.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

make-file-list.sh

@@ -41,6 +41,10 @@ then
 	EXTRA_FILE_EXCLUDES="$EXTRA_FILE_EXCLUDES
 		/mingw$BITNESS/libexec/git-core/git-update"
 fi
+if test -n "$INCLUDE_TMUX"
+then
+	UTIL_PACKAGES="$UTIL_PACKAGES tmux libevent"
+fi
 
 pacman_list () {
 	package_list=$(for arg
@@ -248,3 +252,8 @@ mingw$BITNESS/bin/pdftotext.exe
 mingw$BITNESS/bin/libstdc++-6.dll
 usr/bin/column.exe
 EOF
+
+test -z "$INCLUDE_TMUX" || cat <<EOF
+usr/bin/tmux.exe
+$(ldd /usr/bin/tmux.exe | sed -n 's/.*> \/\(.*msys-event[^ ]*\).*/\1/p')
+EOF