Gentoo musl support expansion

This project is about porting the KDE Plasma desktop to run with the musl libc implementation. Many libraries and applications use "glibc-isms" and therefore cannot compile with musl. This is because musl strives to be a standards-compliant libc implementation which, unlike glibc, doesn't add additional things outside of POSIX. This will be solved by patching out all glibc specific code in software and publishing these changes upstream, and also to the Gentoo repository so already stable software can compile with musl correctly, without waiting for upstream. My deliverables will be having the KDE Plasma desktop & most of the KDE Applications running correctly and passing tests. Documentation for developers wanting to port glibc software and documentation for users for using a Gentoo+musl system will also be added to the Gentoo wiki.