RFC/Ada: removal of $(ADAC)

[Richard Kenner]

    If with the FSF tree, on a system with an installed GNAT in /usr/bin,
    you type the innocent "configure", "make bootstrap" and "make install",
    you can get the system into an inconsistent state requiring $(ADAC)
    to dig you out.

    The problem is that by default make builds and installs gnat but not
    "gnatlib_and_tools" from the gcc/ada subdirectory.  

Right.  You do need to do that.

    My solution, using "ADAC=/usr/bin/gcc", to atleast bootstrap the ada
    front-end, then manually build "gnatlib_and_tools" and install them.
    But for some reason, I still had to install "gnatmake" manually!

I'm not sure sure I understand how that helped, but why wouldn't simply
using CC=/usr/bin/gcc have worked just as well?