RFC: Moving C to its own directory

[Neil Booth]

Following a brief discussion with rth at the summit, and just
now on IRC, I thought I'd post what the current plan is.

1) Create a directory fe/
2) Create a directory fe/c/
3) Move c-specific and C common files, like c-lex.c, there.
4) Move objc/ to fe/ too.

I originally suggested fe/c/c/ fe/c/cp/ and fe/c/objc, but Zack
thought that was overkill and made configury harder, though I
still like the separation myself.

cp/, f/ and java/ and (ugh) ada/ should be moved too, but I'm not
volounteering to do those.

If there are no further comments, I will do 1-4) some time in the
future.  I'm quite busy at present, so it'll probably be at least
2 months.

Neil.