roken: Rename gettimeofday replacement

All replacement roken functions are named rk_blah to avoid symbol
collisions. gettimeofday wasn't being renamed in the header, so fix
that.

This doesn't change the soname of the resulting library, as gettimeofday
isn't currently exported.

lib/roken/roken.h.in

@@ -932,6 +932,7 @@ strptime (const char *, const char *, struct tm *);
 #endif
 
 #ifndef HAVE_GETTIMEOFDAY
+#define gettimeofday rk_gettimeofday
 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 gettimeofday (struct timeval *, void *);
 #endif