Merge branch 'py/commit-comments'

Use git-stripspace to remove comment lines from the commit message. Also
use it to clean up whitespace instead of rolling our own logic.

* py/commit-comments:
  git-gui: remove lines starting with the comment character
diff --git a/git-gui.sh b/git-gui.sh
index 201524c..236bc4e 100755
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -875,6 +875,7 @@
 set default_config(merge.verbosity) 2
 set default_config(user.name) {}
 set default_config(user.email) {}
+set default_config(core.commentchar) "#"
 
 set default_config(gui.encoding) [encoding system]
 set default_config(gui.matchtrackingbranch) false
@@ -3436,6 +3437,10 @@
 	merge         {set txt [mc "Merge Commit Message:"]}
 	*             {set txt [mc "Commit Message:"]}
 	}
+
+	set comment_char [get_config core.commentchar]
+	set txt [string cat $txt \
+				 [mc " (Lines starting with '$comment_char' will be ignored)"]]
 	$ui_coml conf -text $txt
 }
 trace add variable commit_type write trace_commit_type
diff --git a/lib/commit.tcl b/lib/commit.tcl
index 11379f8..23d67d4 100644
--- a/lib/commit.tcl
+++ b/lib/commit.tcl
@@ -141,6 +141,20 @@
 	}
 }
 
+proc strip_msg {msg} {
+	set cmd [concat [list | ] [_git_cmd stripspace] --strip-comments]
+	_trace_exec $cmd
+	set fd [open $cmd r+]
+	fconfigure $fd -translation binary -encoding utf-8
+
+	puts -nonewline $fd $msg
+	close $fd w
+	set result [read $fd]
+	close $fd
+
+	return $result
+}
+
 proc commit_tree {} {
 	global HEAD commit_type file_states ui_comm repo_config
 	global pch_error
@@ -207,8 +221,8 @@
 
 	# -- A message is required.
 	#
-	set msg [string trim [$ui_comm get 1.0 end]]
-	regsub -all -line {[ \t\r]+$} $msg {} msg
+	set msg [strip_msg [$ui_comm get 1.0 end]]
+
 	if {$msg eq {}} {
 		error_popup [mc "Please supply a commit message.