gnat-glade build error on 6.0-BETA2

[Petr Holub]

> I said ADAFLAGS (by analogy to the other variable names, CXXFLAGS,
> FFLAGS, etc); I don't know what ADACFLAGS would stand for :)

I've used ADACFLAGS because you may want to provide different flags to
linker, which would be ADALDFLAGS. For instance, if the application uses
have adasockets (a library for socket manipulation), it would be set
as follows:
ADACFLAGS!=adasockets-config --cflags
ADALDFLAGS!=adasockets-config --libs

Petr