Some architectures (AMDGPU) do not support atomic exchange/fetch for
small types (for AMDGPU: 8- and 16-bit ints). For these types
atomic fetch and atomic exchange needs to be implemeted using atomic
operations on a wider type using cmpxchg.
stage2: change logic for detecting whether the main package is inside
the std package. Previously it relied on realpath() which is not portable.
This uses resolve() which is how imports already work.
* stage2: fix cleanup bug when creating Module
* flatten lib/std/special/* to lib/*
- this was motivated by making main_pkg_is_inside_std false for
compiler_rt & friends.
* rename "mini libc" to "universal libc"
