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"
- approach by Hacker's Delight with wrapping subtraction
- performance expected to be similar to addo
- tests with all relevant combinations of min,max with -1,0,+1 and all
combinations of sequences +-1,2,4..,max
- approach by Hacker's Delight with wrapping addition
- ca. 1.10x perf over the standard approach on my laptop
- tests with all combinations of min,max with -1,0,+1 and combinations of
sequences +-1,2,4..,max