Log Message:
lang/gcc-aux: Change base of gcc 4.7.3 to gcc 4.9.0

It appears that gcc-aux is the first gcc 4.9.0 in pkgsrc.  It's purpose
is to build the Ada packages in pkgsrc, but it also supports C, C++,
Objective-C, and Fortran languages by default.  GCC 4.9 was released on
22 April 2014.

Of note, GCC 4.9 fully supports the new Ada-2012 standard.  The rest of
the changes since GCC 4.8.2 are too numerous to mention, but a decent
summary can be found here: http://gcc.gnu.org/gcc-4.9/changes.html

FreeBSD support was added, but SunOS support was temporarily disabled.
This is due to all new bootstraps being provided, but the SunOS
bootstrap is not yet ready.  Currently supported platforms are

 * NetBSD    i386 and x86-64
 * DragonFly i386 and x86-64
 * FreeBSD   i386 and x86-64

All platform fully pass the Ada testsuite:

 * http://www.dragonlace.net/gnataux/netbsd32/
 * http://www.dragonlace.net/gnataux/netbsd64/
 * http://www.dragonlace.net/gnataux/dragonfly32/
 * http://www.dragonlace.net/gnataux/dragonfly64/
 * http://www.dragonlace.net/gnataux/freebsd32/
 * http://www.dragonlace.net/gnataux/freebsd64/