Add missing includes to timer_test.c and osmo-auc-gen.c

This fixes the build with -Werror-implicit-function-declaration.

taken from malformatted patch of Chí-Thanh Christopher Nguyễn <chithanh@gentoo.org>

tests/timer/timer_test.c

@@ -26,6 +26,7 @@
 #include <stdlib.h>
 #include <signal.h>
 #include <getopt.h>
+#include <unistd.h>
 
 #include <osmocom/core/talloc.h>
 #include <osmocom/core/timer.h>

utils/osmo-auc-gen.c

@@ -26,6 +26,7 @@
 #include <errno.h>
 #include <string.h>
 #include <getopt.h>
+#include <unistd.h>
 
 #include <osmocom/crypt/auth.h>
 #include <osmocom/core/utils.h>