Bug#856274: removal of ada-gcc-name patch causes build failures for non default gnat builds

[Nicolas Boulenguez <nicolas@debian.org>]

Package: gnat-5,gnat-6,gnat-7
Followup-For: Bug #856274

> On gnat-7/7.1.0-7,  the work-around has no effect.
> ARCH-gcc-7-7 is searched but not found.

> what do you mean? that this doesn't work for the cross compilers?

No, simply that on a fresh (x86_64-linux-gnu) chroot:
# apt-get install gnat-7
# echo 'package P is end P;' > p.ads
# /usr/bin/gnatchop p.ads
fails with:
x86_64-linux-gnu-gcc-7-7: installation problem, executable not found

I wonder why /usr/bin/gnatchop exists in the first place.
gnat-6 installs /usr/bin/gnatchop-6
gnat-7 installs /usr/bin/gnatchop-7
Unless I miss something, they are coinstallable and should not *both*
install the /usr/bin/gnatchop symlink.

I suggest that /usr/bin/gnatchop->gnatchop-BV (and the similar
symlinks) is installed by the "gnat" package instead of the "gnat-BV"
package, as done for /usr/bin/gcc.