Build both static and dynamic versions of libfreetype
libftgl cross-building support

 The libftgl autohell build system seems... less than sane. It needs to be
 patched to find our toolchain's opengl (patches shamelessly ripped off from MXE),
 and it needs libfreetype handed to it on a silver platter, both at configure
 time (as an argument) and at build time (in LDFLAGS). Nonetheless it seems to
 work.