Re: GPRbuild compatibility

[Simon Wright <simon@pushface.org>]

I've remembered how I did it now.

gprbuild needs the 'gcc' that it finds in the path to match the target
that it was built with, or you have to tell it the target.

The 'gcc' part means that systems where the GNAT compiler is called
'gnatgcc' will have trouble. Perhaps a symlink

   $ ln -s /usr/bin/gnatgcc ~/bin/gcc

The 'target' part is more tricky. In my case, having fixed up the PATH I
said

   $ gprbuild -v

and near the top I saw

   using project file test_extensions.gpr
   gprconfig --batch -o /Users/simon/gnat-math-extn/test/.build/auto.cgpr --target=x86_64-apple-darwin10.2.0 --config=ada,,
   Error: no matching compiler found for --config=ada,,,,

(note the bit about --target=) but when I say

   $ gcc -v

it says a lot of stuff, in the middle of which is

   Target: x86_64-apple-darwin10

which meant I was able to get gprbuild to recognise this as the compiler
to use by

   $ gprbuild --target=x86_64-apple-darwin10

Of course it's much easier to build gprbuild with the compiler you
intend to use [if you can ;-( ] or, if there is one,to find a way of
fixing this permanently in the gprbuild configuration system.

(in your case, it'd be --target=x86_64-pc-linux-gnu).