Fix pcre_study error check

pcre_study returning NULL is not necessarily an error, from the man page
pcre_study(3):

  "If the function returns NULL, either it could not find any additional
   information, or there was an error. You can tell the difference by
   looking at the error value. It is NULL in first case."

Older libpcre versions would return NULL, causing errors.
pcap: register counters for old pcap versions as well
profiling: when config is missing, keyword profiling is disabled
profiling: don't init rule profiling ctx if rule profiling is disabled
memcmp: don't use SSE intrinsics if less that 16 bytes are available in SSE_4_2 version.
Add SSE support to --build-info