Improve ccc-analyzer error message

[trixirt]

Summary

When ccc-analyzer fails to handle cc args, it outputs only

could not find clang line

To improve this message, print out the errors so now the output
looks like

could not find clang line
Please check errors
clang-12: error: unknown argument: '-fno-ipa-cp-clone'
clang-12: error: unknown argument: '-fno-partial-inlining'

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

 #  Running the analyzer.
 ##----------------------------------------------------------------------------##
 
 sub GetCCArgs {
   my $HtmlDir = shift;
   my $mode = shift;
   my $Args = shift;
   my $line;
+  my $err = "";
   my $OutputStream = silent_system($HtmlDir, $Clang, "-###", $mode, @$Args);
   while (<$OutputStream>) {
+    $err = $err . $_ if ($_ =~ /error:/);
     next if (!/\s"?-cc1"?\s/);
     $line = $_;
   }
-  die "could not find clang line\n" if (!defined $line);
+  if (!defined $line) {
+    print STDERR "could not find clang line\n";
+    print STDERR "Please check errors\n";
+    print STDERR $err;
+    exit 1
+  }
   # Strip leading and trailing whitespace characters.
   $line =~ s/^\s+|\s+$//g;
   my @items = quotewords('\s+', 0, $line);
   my $cmd = shift @items;
   die "cannot find 'clang' in 'clang' command\n" if (!($cmd =~ /clang/));
   return \@items;
 }