git-gui: extract script to generate macOS app

Extract script to generate the macOS app. This change allows us to reuse
the build logic with the Meson build system.

Note that as part of this change we also modify the TKEXECUTABLE
variable to track its full path. Like this we don't have to propagate
both the TKEXECUTABLE and TKFRAMEWORK variables into the script, and the
basename can be trivially computed from TKEXECUTABLE anyway.

Signed-off-by: Patrick Steinhardt <ps@pks.im>

Makefile

@@ -112,7 +112,7 @@ ifeq ($(uname_S),Darwin)
 			TKFRAMEWORK = /System/Library/Frameworks/Tk.framework/Resources/Wish\ Shell.app
                 endif
         endif
-	TKEXECUTABLE = $(shell basename "$(TKFRAMEWORK)" .app)
+	TKEXECUTABLE = $(TKFRAMEWORK)/Contents/MacOS/$(shell basename "$(TKFRAMEWORK)" .app)
 	TKEXECUTABLE_SQ = $(subst ','\'',$(TKEXECUTABLE))
 endif
 
@@ -130,7 +130,6 @@ TCLTK_PATH_SQ = $(subst ','\'',$(TCLTK_PATH))
 
 gg_libdir ?= $(sharedir)/git-gui/lib
 libdir_SQ  = $(subst ','\'',$(gg_libdir))
-libdir_SED = $(subst ','\'',$(subst \,\\,$(gg_libdir_sed_in)))
 exedir     = $(dir $(gitexecdir))share/git-gui/lib
 
 GITGUI_RELATIVE :=
@@ -139,7 +138,6 @@ GITGUI_MACOSXAPP :=
 ifeq ($(exedir),$(gg_libdir))
 	GITGUI_RELATIVE := 1
 endif
-gg_libdir_sed_in := $(gg_libdir)
 ifeq ($(uname_S),Darwin)
         ifeq ($(shell test -d $(TKFRAMEWORK) && echo y),y)
 		GITGUI_MACOSXAPP := YesPlease
@@ -163,22 +161,8 @@ Git\ Gui.app: GIT-VERSION-FILE GIT-GUI-BUILD-OPTIONS \
 		macosx/Info.plist \
 		macosx/git-gui.icns \
 		macosx/AppMain.tcl \
-		$(TKFRAMEWORK)/Contents/MacOS/$(TKEXECUTABLE)
-	$(QUIET_GEN)rm -rf '$@' '$@'+ && \
-	mkdir -p '$@'+/Contents/MacOS && \
-	mkdir -p '$@'+/Contents/Resources/Scripts && \
-	cp '$(subst ','\'',$(subst \,,$(TKFRAMEWORK)/Contents/MacOS/$(TKEXECUTABLE)))' \
-		'$@'+/Contents/MacOS && \
-	cp macosx/git-gui.icns '$@'+/Contents/Resources && \
-	sed -e 's/@@GITGUI_VERSION@@/$(GITGUI_VERSION)/g' \
-		-e 's/@@GITGUI_TKEXECUTABLE@@/$(TKEXECUTABLE)/g' \
-		macosx/Info.plist \
-		>'$@'+/Contents/Info.plist && \
-	sed -e 's|@@gitexecdir@@|$(gitexecdir_SQ)|' \
-		-e 's|@@GITGUI_LIBDIR@@|$(libdir_SED)|' \
-		macosx/AppMain.tcl \
-		>'$@'+/Contents/Resources/Scripts/AppMain.tcl && \
-	mv '$@'+ '$@'
+		$(TKEXECUTABLE)
+	$(QUIET_GEN)$(SHELL_PATH) generate-macos-app.sh . "$@" ./GIT-GUI-BUILD-OPTIONS ./GIT-VERSION-FILE
 endif
 
 ifdef GITGUI_WINDOWS_WRAPPER

generate-macos-app.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+
+set -e
+
+SOURCE_DIR="$1"
+OUTPUT="$2"
+BUILD_OPTIONS="$3"
+VERSION_FILE="$4"
+
+. "$BUILD_OPTIONS"
+. "$VERSION_FILE"
+
+rm -rf "$OUTPUT" "$OUTPUT+"
+
+mkdir -p "$OUTPUT+/Contents/MacOS"
+mkdir -p "$OUTPUT+/Contents/Resources/Scripts"
+
+cp "$TKEXECUTABLE" "$OUTPUT+/Contents/MacOS"
+cp "$SOURCE_DIR/macosx/git-gui.icns" "$OUTPUT+/Contents/Resources"
+sed \
+	-e "s/@@GITGUI_VERSION@@/$GITGUI_VERSION/g" \
+	-e "s/@@GITGUI_TKEXECUTABLE@@/$(basename "$TKEXECUTABLE")/g" \
+	"$SOURCE_DIR/macosx/Info.plist" \
+	>"$OUTPUT+/Contents/Info.plist"
+sed \
+	-e "s|@@gitexecdir@@|$GITGUI_GITEXECDIR|" \
+	-e "s|@@GITGUI_LIBDIR@@|$GITGUI_LIBDIR|" \
+	"$SOURCE_DIR/macosx/AppMain.tcl" \
+	>"$OUTPUT+/Contents/Resources/Scripts/AppMain.tcl"
+mv "$OUTPUT+" "$OUTPUT"

generate-macos-wrapper.sh

@@ -26,7 +26,7 @@ rm -f "$OUTPUT" "$OUTPUT+"
 		echo "git-gui version $GITGUI_VERSION"
 	else
 		libdir="${GIT_GUI_LIB_DIR:-$GITGUI_LIBDIR}"
-		exec "$libdir/Git Gui.app/Contents/MacOS/$TKEXECUTABLE" "$0" "$@"
+		exec "$libdir/Git Gui.app/Contents/MacOS/$(basename "$TKEXECUTABLE")" "$0" "$@"
 	fi
 	EOF
 ) >"$OUTPUT+"