If you want to develop Ada programs and libraries on Debian, please
read the Debian Policy for Ada:
The default Ada compiler is and always will be the package `gnat'.
Debian contains many programs and libraries compiled with it, which
are all ABI-compatible.
Starting with gnat-4.2, Debian provides both zero-cost and
setjump/longjump versions of the run-time library. The zero-cost
exception handling mechanism is the default as it provides the best
performance. The setjump/longjump exception handling mechanism is new
and only provided as a static library. It is necessary to use this
exception handling mechanism in distributed (annex E) programs. If
you wish to use the new sjlj library:
1) call gnatmake with --RTS=sjlj
2) call gnatbind with -static
Do NOT link your programs with libgnat-4.2.so, because it uses the ZCX