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.
actually support libftgl

 To my shame, I forgot all the needed peripheral support stuf yesterday. It
 should actually work now.
Merge branch 'master' into jessie-based - get ftgl stuff
libftgl cleanup

 proper error checking, proper patch attribution
*sigh* the one other piece of machinery I forgot
SDL2 and SDL2_image!

 SDL2 currently gets a minor patch from SDL hg; this will change as of the next
 SDL2 release.
Merge branch 'master' into jessie-based - actually get ftgl; sdl2