[clang][scan-build] Use cc/c++ instead of gcc/g++ on FreeBSD.

[fcambus]

Summary

All supported FreeBSD platforms do not have GCC in base anymore.

[mgorny]

I really hate that we need to hardcode defaults like this but this is outside this patch. IMHO cc/c++ should work everywhere.

[brooks]

Thanks, this will kill off one of the patches in our ports.

clang/tools/scan-build/libexec/ccc-analyzer

 if (`uname -s` =~ m/Darwin/) {
   $DefaultCCompiler = 'clang';
   $DefaultCXXCompiler = 'clang++';
   # Older versions of OSX do not have xcrun to
   # query the SDK location.
   if (-x "/usr/bin/xcrun") {
     $UseXCRUN = 1;
   }
-} elsif (`uname -s` =~ m/OpenBSD/) {
+} elsif (`uname -s` =~ m/(FreeBSD|OpenBSD)/) {
   $DefaultCCompiler = 'cc';
   $DefaultCXXCompiler = 'c++';
 } else {
   $DefaultCCompiler = 'gcc';
   $DefaultCXXCompiler = 'g++';
 }
 
 if ($FindBin::Script =~ /c\+\+-analyzer/) {