use restrict everywhere it's required by c99 and/or posix 2008

to deal with the fact that the public headers may be used with pre-c99
compilers, __restrict is used in place of restrict, and defined
appropriately for any supported compiler. we also avoid the form
[restrict] since older versions of gcc rejected it due to a bug in the
original c99 standard, and instead use the form *restrict.

src/time/timer_create.c

@@ -76,7 +76,7 @@ static void *start(void *arg)
 	return 0;
 }
 
-int timer_create(clockid_t clk, struct sigevent *evp, timer_t *res)
+int timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict res)
 {
 	static pthread_once_t once = PTHREAD_ONCE_INIT;
 	pthread_t td;