cmake BOOST_REGEX_HAS_ICU examples

mapnik/mapnik CMakeLists.txt :171 

list(APPEND MAPNIK_COMPILE_DEFS BOOST_REGEX_HAS_ICU)

mapnik/mapnik CMakeLists.txt :180 

list(APPEND MAPNIK_COMPILE_DEFS BOOST_REGEX_HAS_ICU)

mapnik/mapnik cmake/CheckBoostRegexIcu.cmake :5 

check_cxx_source_runs([[
    #include <boost/regex/icu.hpp>
    #include <unicode/unistr.h>
    int main()
    {
        U_NAMESPACE_QUALIFIER UnicodeString ustr;
        try {
            boost::u32regex pattern = boost::make_u32regex(ustr);
        }
        // an exception is fine, still indicates support is
        // likely compiled into regex
        catch (...) {
            return 0;
        }
        return 0;
    }
    ]] BOOST_REGEX_HAS_ICU)