/// $CompilerFlags: execute("pcre-config --cflags" "PCRE_CXXFLAGS")
/// $LinkerFlags: execute("pcre-config --libs" "PCRE_LDFLAGS" "-lpcre")
+/// $PackageInfo: require_system("centos") pcre-devel pkgconfig
/// $PackageInfo: require_system("darwin") pcre pkg-config
+/// $PackageInfo: require_system("debian") libpcre3-dev pkg-config
/// $PackageInfo: require_system("ubuntu") libpcre3-dev pkg-config