gnatmake and gprbuild

[belteshazzar <gbelteshazzar@gmail.com>]

I'm attempting to build a large system using gnat project files, I
have multiple libraries to be built some that have Ada and C.

Unfortuantely I've found to compile the Ada and C i have to use
gprbuild BUT gprbuild fails (reports a gcc error) to build some of the
large libraries (where as gnatmake WILL build them)

Any ideas?

I think that the command line list of files sent to gcc by gprlib is
to long, but i can't work out how gnatmake doesn't get this same
error.

Any lessons learnt using these tools would be appreciated.