This allows us to link against stripped dylibs. Moreover, it's simply
more correct: The symbol table includes symbols that the dylib uses but
This temporarily regresses our ability to do lazy symbol binding because
dyld_stub_binder isn't in libSystem's export trie. Rather, it is in one
of the sub-libraries libSystem re-exports. (This doesn't affect our
tests since we are mocking out dyld_stub_binder there.) A follow-up diff
will address this by adding support for sub-libraries.
Depends on D79114.