D lang compilers have an option -release (or similar) which turns off
asserts, contracts, and other runtime type checking. This patch wires
that up to the b_ndebug flag.
Fixes#7082
print->print_message is caused because GI does print->print_
in python bindings which is not good.
Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>