ccc-analyzer: Fix -isystem value passing

[Lekensteyn]

Summary

The previous and current regex are broken.

-[D,I,Usystem] matches "-D", "-,", "-I", "-U", "-s" "-y", etc. Besides that, "-isystem /foo" gets interpreted as "-i" with a non-empty value "system" and thus the next "/foo" argument is not read. This patch corrects the regex.

Fixes https://llvm.org/bugs/show_bug.cgi?id=13237

[dcoughlin]

Looks good to me. I will commit.

cfe/trunk/tools/scan-build/ccc-analyzer

if (defined $IgnoredOptionMap{$ArgKey}) {
     my $Cnt = $IgnoredOptionMap{$ArgKey};
     while ($Cnt > 0) {
       ++$i; --$Cnt;
     }
     next;
   }
 
   # Compile mode flags.
-  if ($Arg =~ /^-[D,I,U,isystem](.*)$/) {
+  if ($Arg =~ /^-(?:[DIU]|isystem)(.*)$/) {
     my $Tmp = $Arg;
     if ($1 eq '') {
       # FIXME: Check if we are going off the end.
       ++$i;
       $Tmp = $Arg . $ARGV[$i];
     }
     push @CompileOpts,$Tmp;
     next;