1) Python3 needs the util-linux:host dependency otherwise uuid support will
leak over from the build host during a clean build, only to use util-linux:host
for uuid support during a subsequent rebuild (which fails, because of #2)
2) util-linux:host needs -fPIC as this is what Python3 requires (clean builds
work because of #1...)
3) Remove toolchain from util-linux:host to avoid a circular toolchain
reference now that Python3 is also part of toolchain (via meson)
bd049eb269