When I used this method a few years ago, with Ada from the Ubuntu repository, it worked fine. Now, with my installation from Adacore, not so anymore.
The method consists of 2 commands (time.h as example)
While the first command executes without any problem, the second one returns:
gcc: fatal error: cannot execute ‘gnat1’: execvp: No such file or directory
It doesn't depend on the -gnat05 option. There is indeed no gnat1 in the bin directory of the Ada installation. Mine is version 2021. I am reluctant to install the GNU version in parallel, I might mix up things.
Any other idea?
"my installation from AdaCore" - which one?
It may be that the gcc you pick up doesn’t understand Ada at all. Normally a gcc from an Ada installation knows to delegate compilations to the Ada subsystem.
You might have better luck with
gnatmake -c -u -f *.ads
-c - compile only, even if it looks like a main unit-u - just this unit, not the closure-f - compile even if Ada’s rules mean it doesn’t need it