RTS linker fails due to redefinition of atexit() under musl

GHC currently includes atexit in its RtsSymbols due to #4456 (closed). However, this causes trouble when linking statically against musl. Specifically, the RTS linker will attempt to load libc.a, which includes a non-weak definition of the atexit symbol, causing a symbol conflict (something first observed in !5147 (closed)).

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information