lib/precise_time.c: Remove dead code

The last branch of `#if _POSIX_TIMERS` was missing a declaration of
"showme". Since that variable is not used anywhere, just drop it.

lib/precise_time.c

@@ -53,15 +53,8 @@ double monotonic_seconds()
 
 #include <time.h>
 
-static int showme = 0;
-
 double monotonic_seconds()
 {
-    if (showme)
-    {
-        showme = 0;
-    }
-
     struct timespec time;
 
     // Note: Make sure to link with -lrt to define clock_gettime.
@@ -170,11 +163,6 @@ static void __attribute__((constructor)) init_rdtsc_per_sec()
 
 double monotonic_seconds()
 {
-    if (showme)
-    {
-        showme = false;
-    }
-
     return (double) rdtsc() / (double) rdtsc_per_sec;
 }