boolean: accept yes and no as well

Signed-off-by: Junio C Hamano <junkio@cox.net>

config.c

diff --git a/config.c b/config.c
index b23f4bf..8445f7d 100644
--- a/config.c
+++ b/config.c
@@ -244,9 +244,9 @@
 		return 1;
 	if (!*value)
 		return 0;
-	if (!strcasecmp(value, "true"))
+	if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
 		return 1;
-	if (!strcasecmp(value, "false"))
+	if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
 		return 0;
 	return git_config_int(name, value) != 0;
 }