git-prompt.sh: if pc mode, immediately set PS1 to a plain prompt

diff --git a/git-difftool.perl b/git-difftool.perl
index 9a1054a2bb9d72d10aeb88c6bdf1d47b0fde1a75..7df7c8a9a7c889fbf5f0b2d6e67be66bf6fea6b1 100755 (executable)
--- a/git-difftool.perl
+++ b/git-difftool.perl
@@ -47,13 +47,9 @@ sub find_worktree
 
 sub print_tool_help
 {
-       my $cmd = 'TOOL_MODE=diff';
-       $cmd .= ' && . "$(git --exec-path)/git-mergetool--lib"';
-       $cmd .= ' && show_tool_help';
-
        # See the comment at the bottom of file_diff() for the reason behind
        # using system() followed by exit() instead of exec().
-       my $rc = system('sh', '-c', $cmd);
+       my $rc = system(qw(git mergetool --tool-help=diff));
        exit($rc | ($rc >> 8));
 }