initdb: make safe_create_dir public

Soon we will want to create initdb functions for ref backends, and
code from initdb that calls this function needs to move into the files
backend. So this function needs to be public.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>

cache.h

@@ -1747,4 +1747,12 @@ void stat_validity_update(struct stat_validity *sv, int fd);
 int versioncmp(const char *s1, const char *s2);
 void sleep_millisec(int millisec);
 
+/*
+ * Create a directory and (if share is nonzero) adjust its permissions
+ * according to the shared_repository setting. Only use this for
+ * directories under $GIT_DIR.  Don't use it for working tree
+ * directories.
+ */
+void safe_create_dir(const char *dir, int share);
+
 #endif /* CACHE_H */