[Bug ada/120106] replace hardcoded gnatmake commands with configuration variables

[doko at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120106

--- Comment #19 from Matthias Klose <doko at gcc dot gnu.org> ---
but why first configure it with the "wrong" gnatmake, and then override it for
the build?