patch for -Wno-long-long and early GNAT compilers

[Richard Kenner]

    Please don't split hairs.  We went over this at length last year; the
    Ada front end in the released GCC 3.1 has to be buildable with the
    commonly available gnat-3.13.  

In general, GNAT is only buildable by the previous version of GNAT
because it may use features added in that version.  The GNAT sources
in the FSF tree are close to GNAT 3.15, so you need 3.14 to build, not
3.13.  I believe that, in this case, 3.13 does indeed work, but the problem
is that some of the "3.13" versions out there are of unknown origin, so
it's not clear exactly what they are.

    And I want to go on record as saying that it *should* be buildable
    with *any* standard-compliant Ada compiler.

Due to the tight linkage with C code (the rest of GCC0, that's not at
all practical, unfortunately.