When an installed static library A links to an internal static library B
built using a custom_target(), raise an error instead of a warning. This
is because to be usable, A needs to contain B which would require to
extract the archive to get its objects files.
This used to work, but was printing a warning and was installing a
broken static library, because we used to overlink in many cases, and
that got fixed in Meson 1.2.0. It now fails at link time with symbols
from the custom target not being defined. It's better to turn the
warning into a hard error at configure time.
While at it, noticed this situation can happen for any internal custom
or rust target we link to, recursively.
get_internal_static_libraries_recurse() could be called on CustomTarget
objects which do not implement it, and even if we did not call that
method, it would still fail when trying to call extract_all_objects() on
it.
Fixes: #12006
926c3a6919