bug 18556 - tolower & locales

Hi! I've prepared a fix for bug #18556 - see https://github.com/php/php-src/pull/126 A slight complication there is that for internal operations we probably want locale-independent lowercasing, while for regular string operations we probably want to stay with locale-depenedent one. That's how I implemented it, even though it adds a bit of complexity, but I think it's the best way to solve it. Any comments/objections/improvements? Johannes, is it ok to put this fix into 5.3 too? -- Stanislav Malyshev, Software Architect SugarCRM: http://www.sugarcrm.com/ (408)454-6900 ext. 227