Merge git-gui into ml/git-gui-exec-path-fix

* git-gui:
  git-gui - use git-hook, honor core.hooksPath
  git-gui - re-enable use of hook scripts

diff --combined git-gui/git-gui.sh
index 8bc8892c400a0866f814bff2db54f00349d89565,3e5907a4609b1510aef71ab54f56a82eeb36e071..3e5907a4609b1510aef71ab54f56a82eeb36e071
--- 1/git-gui/git-gui.sh
--- 2/git-gui.sh
+++ b/git-gui/git-gui.sh
@@@ -118,7 -118,7 +118,7 @@@ proc sanitize_command_line {command_lin
        set i $from_index
        while {$i < [llength $command_line]} {
                set cmd [lindex $command_line $i]
-               if {[file pathtype $cmd] ne "absolute"} {
+               if {[llength [file split $cmd]] < 2} {
                        set fullpath [_which $cmd]
                        if {$fullpath eq ""} {
                                throw {NOT-FOUND} "$cmd not found in PATH"
@@@ -661,31 -661,8 +661,8 @@@ proc git_write {args} 
  }
  
  proc githook_read {hook_name args} {
-       set pchook [gitdir hooks $hook_name]
-       lappend args 2>@1
- 
-       # On Windows [file executable] might lie so we need to ask
-       # the shell if the hook is executable.  Yes that's annoying.
-       #
-       if {[is_Windows]} {
-               upvar #0 _sh interp
-               if {![info exists interp]} {
-                       set interp [_which sh]
-               }
-               if {$interp eq {}} {
-                       error "hook execution requires sh (not in PATH)"
-               }
- 
-               set scr {if test -x "$1";then exec "$@";fi}
-               set sh_c [list $interp -c $scr $interp $pchook]
-               return [_open_stdout_stderr [concat $sh_c $args]]
-       }
- 
-       if {[file executable $pchook]} {
-               return [_open_stdout_stderr [concat [list $pchook] $args]]
-       }
- 
-       return {}
+       set cmd [concat git hook run --ignore-missing $hook_name -- $args 2>@1]
+       return [_open_stdout_stderr $cmd]
  }
  
  proc kill_file_process {fd} {