Makefile.m32: fix regression with tool_hugehelp [ci skip]

Makefile.m32: fix regression with tool_hugehelp [ci skip]

In a recent commit I mistakenly deleted this logic, after seeing a
reference to a filename ending with `.cvs` and thinking it must have
been long gone. Turns out this is an existing file. Restore the rule
and the necessary `COPY` definitions with it.

The restored logic is required for a successful build on a bare source
tree (as opposed to a source release tarball).

Also shorten an existing condition similar to the one added in this
patch.

Regression since 07a0047882dd3f1fbf73486c5dd9c15370877ad6

Closes #9645