[PATCH 3/6] config: make a copy of $GIT_CONFIG string

[Jeff King <peff@peff.net>]

cmd_config() points our source filename pointer at the return value of
getenv(), but that value may be invalidated by further calls to
environment functions. Let's copy it to make sure it remains valid.

We don't need to bother freeing it, as it remains part of the
whole-process global state until we exit.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/config.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/builtin/config.c b/builtin/config.c
index 84385ef165..2db4e763e7 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -598,7 +598,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 	int nongit = !startup_info->have_repository;
 	char *value;
 
-	given_config_source.file = getenv(CONFIG_ENVIRONMENT);
+	given_config_source.file = xstrdup_or_null(getenv(CONFIG_ENVIRONMENT));
 
 	argc = parse_options(argc, argv, prefix, builtin_config_options,
 			     builtin_config_usage,
-- 
2.20.1.651.g2d41a78c67