Reapply gdlpp changes on new fcpp upstream

[bgermann]

The fcpp fork bkaradzic/fcpp is actively developed and holds a lot of improvements compared to the original bagder/fcpp that seems to be dead. This PR imports the bkaradzic/fcpp version, adds most of the gdlpp changes as patches and applies them. The patches are kept to be able to import any upstream changes easily. The change that is referenced in #5 is left out. Therefore this closes #5.

Upstream's makefile is not imported in favour of the existing Makefile.am and gdlpp.mak. Also, the fpp.{exp,fd} files are ignored.

[nrsiward]

We'll look at merging it after the upcoming release.

• This large of a change to gdlpp requires significant testing, and we don't want to hold up the release.

• We also have to decide if we want to pull from upstream. In the past we've considered this a frozen part of GrCompiler since it provided adequate functionality for us.