default system toolchain and compiler
default system linker
default system C runtime library
default system OpenMP library
default system "coreutils"
experimental attempt to bring the BSD utils to Linux
also checkout this project https://github.com/uutils/coreutils
The entire stack is completely GNU-free and (except coreutils) is proven to work. I'm running a GNU-free Gentoo Linux as my daily driver. I get my entire work done there, including but not limited to development, web browsing, chatting with friends, gaming (requires a GNU compatibility layer) and more...
Minor Warning: There is software which hard depends on GNU though which requires portability patches :(
btw I don't use GNU :^)