the initial-exec tls model is not valid in any code that might be
dynamically loaded. it usually happens to work on glibc because glibc
reserves some static tls space for late-loaded libraries that need it,
but if it's already been exhausted that will fail. musl does not
support this hack at all, and it's not valid for gcc target libs to be
doing it anywhere, so patch it out entirely rather than just for musl.
e3e354f63a