Rename C files to .c in GCC source

[Kevin Ingwersen (Ingwie Phoenix)]

> Am 31.01.2015 um 21:21 schrieb DJ Delorie <dj@redhat.com>:
> 
> 
>> Aren't current Windows file systems case-preserving?  Then they
>> shouldn't have no problems with .C files.
> 
> They are case preserving, but not case sensitive.  A wildcard search
> for *.c will match foo.C and bar.c, and foo.c can be opened as FOO.C.
That also applies to OS X:

$ head -n 1 build.it
/**
$ head -n 1 BUILD.IT
/**
$ head -n 1 BuIlD.iT
/**