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
This allows users to disable writing out the inbuilt variables to
the pkg-config file as they might actualy not be required.
One reason to have this is for architecture-independent pkg-config
files in projects which also have architecture-dependent outputs.
For example : https://gitlab.freedesktop.org/wayland/weston/issues/269Fixes#4011
The main library must come before extra libraries, because they are
likely to be dependencies of the main library that get promoted from
private to public. This was causing static link issues with glib-2.0.pc.