Log Message:
lang/gcc5-aux: Reduce functionality to allow build on NetBSD 7

There are three major issues with gcc5-aux on NetBSD 7.0 Beta.

1) The gold linker fails in the middle of the build with an
   "operation not permitted" error.  I believe this is either an issue
   directory with NetBSD 7.0 beta (not seen on 6.99) or an issue with
   the binutils 2.25 from pkgsrc.

It turns out that NetBSD 7.0 uses binutils 2.23 which is new enough.
By removing the requirement for using pkgsrc binutils, it will build
until it hits issue #2 which is ...

2) Fortran no longer builds on NetBSD 7.0.  Something about an "old"
   version of locale symbol.  Something changed with locales and gcc5's
   Fortran does not like it.

The solution is to turn off fortran and objc options by default.  This
means only C, C++, and Ada languages are supported by default.  Obviously
this is not a "solution" but it will have to do for now.

3) The signal trampoline has changed.  The pattern for the signal
   trampoline has been altered and now the NetBSD unwind support can't
   recognize the end of the stack.  This causes all the stack overflow
   and stack check tests to fail.

I didn't do anything here.  It requires a lot of work with gdb to figure
out what the new pattern looks like and I don't have any sort of time
for that.  Stack handling still works for NetBSD 5 and 6 though.