enabling top-level access to this config supports the effort to enable
`strictDeps` by default:
<https://github.com/NixOS/nixpkgs/issues/178468>
PRs to support musl, static, and cross compiled builds benefit from
simple instructions the reviewer can observe improvements, e.g.:
- "fixes build for `pkgsMusl.hello`"
- "fixes `nix-build -A pkgsStatic.hello`"
- "fixes `pkgsCross.aarch64-multiplatform.hello`"
now strictDeps-related changes can benefit from this same idiom:
- "fixes build for `pkgsStrict.hello`"
as with glibcxxassertions, we don't yet have a nice mechanism
for deferring support decisions to the c++ library in use, so
for now at least enabling this hardening flag will cause
_LIBCPP_HARDENING_MODE to be defined on all compilers
no platforms "unsupported" because we don't have a nice
mechanism for determining a platform's c++ lib and the flag
should be harmlessly ignored by a other c++ libs
There's nothing that relies on this. We want to get rid of pcre and if something specifically needs to be compiled with 16-bit code unit support they can do that with pcre2 instead
