Regular darwin builds

[FX]

Hi all,

I’ve set up daily builds and regtests on a darwin box. The results should appear directly on gcc-testresults (https://gcc.gnu.org/ml/gcc-testresults/current/).
This should, in the future, help track down regressions affecting darwin (PIC-related, in particular!).

The hardware is new, the OS is the latest and greatest (x86_64-apple-darwin14), and will be updated to keep it that way. However, it’s not very powerful (it’s a Mac Mini). Bootstrap (C, C++, Obj-C, Obj-C++, Fortran, Java, LTO) takes about 2 hours, regtesting both 32 and 64-bit takes a bit over 3 hours.

I plan to schedule it for:

  - daily bootstrap + regtest of trunk
  - weekly bootstrap of latest release branch (currently 4.9)

If you have other ideas, I’m open to suggestions.

FX