workaround for gcc's optimizer breaking dynamic symbol resolution

src/time/clock_gettime.c

@@ -5,7 +5,7 @@
 #include "libc.h"
 
 int __vdso_clock_gettime(clockid_t, struct timespec *) __attribute__((weak));
-static int (*const cgt)(clockid_t, struct timespec *) = __vdso_clock_gettime;
+static int (*cgt)(clockid_t, struct timespec *) = __vdso_clock_gettime;
 
 int __clock_gettime(clockid_t clk, struct timespec *ts)
 {
@@ -14,6 +14,7 @@ int __clock_gettime(clockid_t clk, struct timespec *ts)
 	r = __syscall(SYS_clock_gettime, clk, ts);
 	if (!r) return r;
 	if (r == -ENOSYS) {
+		cgt = 0;
 		if (clk == CLOCK_REALTIME) {
 			__syscall(SYS_gettimeofday, clk, ts, 0);
 			ts->tv_nsec = (int)ts->tv_nsec * 1000;