+ next if $line =~ /^\s*(?:C\s+)?
+ (?:C|c)ompiler[\s.]*:\s+
+ $cc_regex
+ (?:\s-std=[a-z0-9:+]+)?\s*$
+ /x
+ or $line =~ /^\s*(?:- )?(?:CC|CXX)\s*=\s*$cc_regex\s*$/
+ or $line =~ /^\s*-- Check for working (?:C|CXX) compiler: /
+ or $line =~ /^\s*(?:echo )?Using [A-Z_]+\s*=\s*/;
+ # Debian buildd output.
+ next if $line =~ /^\s*Depends: .*?$cc_regex.*?$/
+ and $line !~ /\s-./; # option, prevent false negatives
+