user-manual: Explain what submodules are good for.

diff --git a/pack-write.c b/pack-write.c
index 1cf5f7c9f0956a457de03c64238d298a9d996984..e59b197e5ebb301107f9a18b7765e18097a1c8e3 100644 (file)
--- a/pack-write.c
+++ b/pack-write.c
@@ -45,7 +45,7 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
                static char tmpfile[PATH_MAX];
                snprintf(tmpfile, sizeof(tmpfile),
                         "%s/tmp_idx_XXXXXX", get_object_directory());
-               fd = mkstemp(tmpfile);
+               fd = xmkstemp(tmpfile);
                index_name = xstrdup(tmpfile);
        } else {
                unlink(index_name);