There is not much use in GLib: on Windows, we have a native API for
string collation, and the rest uses either libicu or the standard C
library calls.

We don't need this anymore: Win32 doesn't use this library at all, and
everything else has either iconv() or libicu.

New in clang 3.6.

Prepare for a ICU-based backend without GLib.

Again, POSIX says strcasecmp is not in string.h.

Make valgrind happy.

Turns out ucol_getSortKey() does not what I thought it does.