ANN: GCC 5.2.0 for OS X El Capitan

[Simon Wright <simon@pushface.org>]

This compiler (native only at time of writing) is on Sourceforge[1].

There's not a lot of added Ada goodness compared to 5.1.0, but the El
Capitan-related problem that David Botton recently encountered (see also
[2]) is fixed.

If you need PR66509 fixed and also arm-eabi support, put this compiler
on your PATH before the 5.1.0 compiler
(e.g. PATH=/opt/gcc-5.2.0/bin:/opt/gcc-5.1.0/bin:/the/rest/of/your/path)

I don't have a computer with Mavericks installed, any brave soul care to
give it a try?

[1]
https://sourceforge.net/projects/gnuada/files/GNAT_GCC%20Mac%20OS%20X/5.2.0/
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66509