Make the includes be libkmod/libkmod.h for code outside of library. This
fixes the broken build after 1315123 ('build-sys: Don't add libkmod
subdirectory to include path').
It has changed in the past, and these days, anyone can get a copy of the
LGPL via the web rather than by post.
Like 657a122 (Remove FSF mailing address) in libabc by Josh Tripplet,
but let the FSF website in which the license can be found.
stdout and stderr are names reserved for the implementation
and musl uses them rightfully as macro - and the expansion
causes (of course) unexpected results.
rename the struct members stdout to out and stderr
to err, to be 1) compliant 2) cause compilation to
succeed.
fixes build with musl libc.
