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
Extend platform_fix_name() to handle this case
We avoid using library(version:), so we don't have to teach
platform_fix_name() all the platform details of versioned shared library
naming. Hopefully that's exercised by platform-specific tests...