*: introduce and use FAST_FUNC: regparm on i386, otherwise no-on
text data bss dec hex filename
808035 611 6868 815514 c719a busybox_old
804472 611 6868 811951 c63af busybox_unstripped
diff --git a/libbb/change_identity.c b/libbb/change_identity.c
index da840bf..619db09 100644
--- a/libbb/change_identity.c
+++ b/libbb/change_identity.c
@@ -31,7 +31,7 @@
#include "libbb.h"
/* Become the user and group(s) specified by PW. */
-void change_identity(const struct passwd *pw)
+void FAST_FUNC change_identity(const struct passwd *pw)
{
if (initgroups(pw->pw_name, pw->pw_gid) == -1)
bb_perror_msg_and_die("can't set groups");