git-gui: try to provide a window icon under X

When running under X, we try to set up a window icon by providing a
hand-crafted 16x16 Tk photo image equivalent to the .ico. Wrap in a
catch because the earlier Tcl/Tk 8.4 releases didn't provide the 'wm
iconphoto' command.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

git-gui.sh

@@ -597,6 +597,28 @@ if {[is_Windows]} {
 	if {![info exists env(DISPLAY)]} {
 		set env(DISPLAY) :9999
 	}
+} else {
+	catch {
+		image create photo gitlogo -width 16 -height 16
+
+		gitlogo put #33CC33 -to  7  0  9  2
+		gitlogo put #33CC33 -to  4  2 12  4
+		gitlogo put #33CC33 -to  7  4  9  6
+		gitlogo put #CC3333 -to  4  6 12  8
+		gitlogo put gray26  -to  4  9  6 10
+		gitlogo put gray26  -to  3 10  6 12
+		gitlogo put gray26  -to  8  9 13 11
+		gitlogo put gray26  -to  8 11 10 12
+		gitlogo put gray26  -to 11 11 13 14
+		gitlogo put gray26  -to  3 12  5 14
+		gitlogo put gray26  -to  5 13
+		gitlogo put gray26  -to 10 13
+		gitlogo put gray26  -to  4 14 12 15
+		gitlogo put gray26  -to  5 15 11 16
+		gitlogo redither
+
+		wm iconphoto . -default gitlogo
+	}
 }
 
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