git-gui: Guess our share/git-gui/lib path at runtime if possible

Johannes Sixt asked me to try to avoid embedding the runtime location
of git-gui's library directory in the executable script.  Not embedding
it helps the MinGW to be relocatable to another directory should a user
wish to install the programs in a directory other than the location the
packager wanted them to be installed into.

Most of this is a hack.  We try to determine if the path of our master
git-gui script will be able to locate the lib by ../share/git-gui/lib.
This should be true if $(gitexecdir) and $(libdir) have the same prefix.
If they do then we defer the assignment of $(libdir) until runtime, and
we get it from $argv0 rather than embedding it into the script itself.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Makefile

@@ -11,6 +11,7 @@ SCRIPT_SH = git-gui.sh
 GITGUI_BUILT_INS = git-citool
 ALL_PROGRAMS = $(GITGUI_BUILT_INS) $(patsubst %.sh,%,$(SCRIPT_SH))
 ALL_LIBFILES = $(wildcard lib/*.tcl)
+PRELOAD_FILES = lib/class.tcl
 
 ifndef SHELL_PATH
 	SHELL_PATH = /bin/sh
@@ -21,7 +22,7 @@ ifndef gitexecdir
 endif
 
 ifndef sharedir
-	sharedir := $(dir $(gitexecdir))/share
+	sharedir := $(dir $(gitexecdir))share
 endif
 
 ifndef INSTALL
@@ -32,6 +33,7 @@ ifndef V
 	QUIET_GEN      = @echo '   ' GEN $@;
 	QUIET_BUILT_IN = @echo '   ' BUILTIN $@;
 	QUIET_INDEX    = @echo '   ' INDEX $(dir $@);
+	QUIET_2DEVNULL = 2>/dev/null
 endif
 
 TCL_PATH   ?= tclsh
@@ -45,17 +47,25 @@ endif
 DESTDIR_SQ = $(subst ','\'',$(DESTDIR))
 gitexecdir_SQ = $(subst ','\'',$(gitexecdir))
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
+TCL_PATH_SQ = $(subst ','\'',$(TCL_PATH))
 TCLTK_PATH_SQ = $(subst ','\'',$(TCLTK_PATH))
 
 libdir   ?= $(sharedir)/git-gui/lib
 libdir_SQ = $(subst ','\'',$(libdir))
 
+exedir    = $(dir $(gitexecdir))share/git-gui/lib
+exedir_SQ = $(subst ','\'',$(exedir))
+
 $(patsubst %.sh,%,$(SCRIPT_SH)) : % : %.sh
 	$(QUIET_GEN)rm -f $@ $@+ && \
+	if test '$(exedir_SQ)' = '$(libdir_SQ)'; then \
+		GITGUI_RELATIVE=1; \
+	fi && \
 	sed -e '1s|#!.*/sh|#!$(SHELL_PATH_SQ)|' \
 		-e 's|^exec wish "$$0"|exec $(subst |,'\|',$(TCLTK_PATH_SQ)) "$$0"|' \
 		-e 's/@@GITGUI_VERSION@@/$(GITGUI_VERSION)/g' \
-		-e 's|@@GITGUI_LIBDIR@@|$(libdir_SQ)|' \
+		-e 's|@@GITGUI_RELATIVE@@|'$$GITGUI_RELATIVE'|' \
+		-e $$GITGUI_RELATIVE's|@@GITGUI_LIBDIR@@|$(libdir_SQ)|' \
 		$@.sh >$@+ && \
 	chmod +x $@+ && \
 	mv $@+ $@
@@ -64,17 +74,28 @@ $(GITGUI_BUILT_INS): git-gui
 	$(QUIET_BUILT_IN)rm -f $@ && ln git-gui $@
 
 lib/tclIndex: $(ALL_LIBFILES)
-	$(QUIET_INDEX)echo \
+	$(QUIET_INDEX)if echo \
-	  source lib/class.tcl \; \
+	  $(foreach p,$(PRELOAD_FILES),source $p\;) \
 	  auto_mkindex lib '*.tcl' \
-	| $(TCL_PATH)
+	| $(TCL_PATH) $(QUIET_2DEVNULL); then : ok; \
+	else \
+	 echo 1>&2 "    * $(TCL_PATH) failed; using unoptimized loading"; \
+	 rm -f $@ ; \
+	 echo '# Autogenerated by git-gui Makefile' >$@ && \
+	 echo >>$@ && \
+	 $(foreach p,$(PRELOAD_FILES) $(ALL_LIBFILES),echo '$(subst lib/,,$p)' >>$@ &&) \
+	 echo >>$@ ; \
+	fi
 
 # These can record GITGUI_VERSION
 $(patsubst %.sh,%,$(SCRIPT_SH)): GIT-VERSION-FILE GIT-GUI-VARS
+lib/tclIndex: GIT-GUI-VARS
 
 TRACK_VARS = \
 	$(subst ','\'',SHELL_PATH='$(SHELL_PATH_SQ)') \
+	$(subst ','\'',TCL_PATH='$(TCL_PATH_SQ)') \
 	$(subst ','\'',TCLTK_PATH='$(TCLTK_PATH_SQ)') \
+	$(subst ','\'',gitexecdir='$(gitexecdir_SQ)') \
 	$(subst ','\'',libdir='$(libdir_SQ)') \
 #end TRACK_VARS
 

git-gui.sh

@@ -25,10 +25,41 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA}
 ## configure our library
 
 set oguilib {@@GITGUI_LIBDIR@@}
-if {[string match @@* $oguilib]} {
+set oguirel {@@GITGUI_RELATIVE@@}
+if {$oguirel eq {1}} {
+	set oguilib [file dirname [file dirname [file normalize $argv0]]]
+	set oguilib [file join $oguilib share git-gui lib]
+} elseif {[string match @@* $oguirel]} {
 	set oguilib [file join [file dirname [file normalize $argv0]] lib]
 }
-set auto_path [concat [list $oguilib] $auto_path]
+set idx [file join $oguilib tclIndex]
+catch {
+	set fd [open $idx r]
+	if {[gets $fd] eq {# Autogenerated by git-gui Makefile}} {
+		set idx [list]
+		while {[gets $fd n] >= 0} {
+			if {$n ne {} && ![string match #* $n]} {
+				lappend idx $n
+			}
+		}
+	} else {
+		set idx {}
+	}
+	close $fd
+}
+if {$idx ne {}} {
+	set loaded [list]
+	foreach p $idx {
+		if {[lsearch -exact $loaded $p] >= 0} continue
+		puts $p
+		source [file join $oguilib $p]
+		lappend loaded $p
+	}
+	unset loaded p
+} else {
+	set auto_path [concat [list $oguilib] $auto_path]
+}
+unset -nocomplain oguilib oguirel idx fd
 
 if {![catch {set _verbose $env(GITGUI_VERBOSE)}]} {
 	unset _verbose
@@ -1179,15 +1210,12 @@ foreach class {Button Checkbutton Entry Label
 }
 unset class
 
-if {[is_Windows]} {
+if {[is_MacOSX]} {
-	set M1B Control
-	set M1T Ctrl
-} elseif {[is_MacOSX]} {
 	set M1B M1
 	set M1T Cmd
 } else {
-	set M1B M1
+	set M1B Control
-	set M1T M1
+	set M1T Ctrl
 }
 
 proc apply_config {} {