Index: uspace/lib/c/include/sys/time.h
===================================================================
--- uspace/lib/c/include/sys/time.h	(revision 56b308ef8e694f7c971ad48610f169a77582c9dc)
+++ uspace/lib/c/include/sys/time.h	(revision af7e3d3496ea703ca013f4d376c365cfbf0f2141)
@@ -84,4 +84,5 @@
 extern struct tm *localtime(const time_t *timer);
 extern char *ctime(const time_t *timer);
+extern double difftime(time_t time1, time_t time0);
 extern size_t strftime(char *restrict s, size_t maxsize,
     const char *restrict format, const struct tm *restrict tm);