[PATCH v2 resend] gitk: Use an external icon file on Windows

[Sebastian Schuberth <sschuberth@gmail.com>]

Git for Windows now ships with the new Git icon from git-scm.com. Use that
icon file instead of the old procedurally drawn one if it exists.

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
---
 gitk-git/gitk | 49 ++++++++++++++++++++++++++-----------------------
 1 file changed, 26 insertions(+), 23 deletions(-)

diff --git a/gitk-git/gitk b/gitk-git/gitk
index 59693c0..5127e55 100755
--- a/gitk-git/gitk
+++ b/gitk-git/gitk
@@ -11664,7 +11664,6 @@ if { [info exists ::env(GITK_MSGSDIR)] } {
     set gitk_prefix [file dirname [file dirname [file normalize $argv0]]]
     set gitk_libdir [file join $gitk_prefix share gitk lib]
     set gitk_msgsdir [file join $gitk_libdir msgs]
-    unset gitk_prefix
 }
 
 ## Internationalization (i18n) through msgcat and gettext. See
@@ -11821,28 +11820,32 @@ if {[expr {[exec git rev-parse --is-inside-work-tree] == "true"}]} {
 set worktree [exec git rev-parse --show-toplevel]
 setcoords
 makewindow
-catch {
-    image create photo gitlogo      -width 16 -height 16
-
-    image create photo gitlogominus -width  4 -height  2
-    gitlogominus put #C00000 -to 0 0 4 2
-    gitlogo copy gitlogominus -to  1 5
-    gitlogo copy gitlogominus -to  6 5
-    gitlogo copy gitlogominus -to 11 5
-    image delete gitlogominus
-
-    image create photo gitlogoplus  -width  4 -height  4
-    gitlogoplus  put #008000 -to 1 0 3 4
-    gitlogoplus  put #008000 -to 0 1 4 3
-    gitlogo copy gitlogoplus  -to  1 9
-    gitlogo copy gitlogoplus  -to  6 9
-    gitlogo copy gitlogoplus  -to 11 9
-    image delete gitlogoplus
-
-    image create photo gitlogo32    -width 32 -height 32
-    gitlogo32 copy gitlogo -zoom 2 2
-
-    wm iconphoto . -default gitlogo gitlogo32
+if {$::tcl_platform(platform) eq {windows} && [file exists $gitk_prefix/etc/git.ico]} {
+    wm iconbitmap . -default $gitk_prefix/etc/git.ico
+} else {
+    catch {
+        image create photo gitlogo      -width 16 -height 16
+
+        image create photo gitlogominus -width  4 -height  2
+        gitlogominus put #C00000 -to 0 0 4 2
+        gitlogo copy gitlogominus -to  1 5
+        gitlogo copy gitlogominus -to  6 5
+        gitlogo copy gitlogominus -to 11 5
+        image delete gitlogominus
+
+        image create photo gitlogoplus  -width  4 -height  4
+        gitlogoplus  put #008000 -to 1 0 3 4
+        gitlogoplus  put #008000 -to 0 1 4 3
+        gitlogo copy gitlogoplus  -to  1 9
+        gitlogo copy gitlogoplus  -to  6 9
+        gitlogo copy gitlogoplus  -to 11 9
+        image delete gitlogoplus
+
+        image create photo gitlogo32    -width 32 -height 32
+        gitlogo32 copy gitlogo -zoom 2 2
+
+        wm iconphoto . -default gitlogo gitlogo32
+    }
 }
 # wait for the window to become visible
 tkwait visibility .
-- 
1.7.11.msysgit.2