outside */dist/* subdirectories.
When USE_PIGZGZIP=yes, bsd.own.mk sets TOOL_GZIP=${TOOL_PIGZ},
so there's no need to test USE_PIGZGZIP in these Makefiles.
Based on PR port-powerpc/40421 from Wojciech Galazka,
with misc tweaks by me.
Note sysinst part is not pulled because there is
no supported storage device yet on this port.