https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71072
--- Comment #2 from nicolas.boulenguez at free dot fr --- Does examples/first_steps/ada_main.gpr trigger the failure? And the same project with the C library removed? Once you have a minimal reproducer, you may get the exact compiler invokations with "gprbuild -v" (normal output is misleading).