Features will come in slowly while I restructure for gint 3. With this
third big target for gint, the legacy aspects of gint 2's structure and
API are getting felt, so a major revision will be in order.
See the TODO file at this commit for info on what works and not.
Nothing interesting in this commit, just moving files around, making
sure every target compiles every file, and controlling with macros
instead.
Basic support for fxg3a target in CMakeLists.txt, cmake/FindGint.cmake,
giteapc.make and include/gint/config.h.in. The rest is forgettable.
Known limitation: OpenLibm can't be installed out of the compiler prefix
yet (because of that pesky openlibm/ prefix that it installs to but does
not use when including).
