sezero authored Oct 08, 2019 and Erik de Castro Lopo committed Oct 10, 2019

When building in the same directory as the source, it works, but not in
a separate directory.  The trailing slash is important with nasm.  Note
that include_directories("${CMAKE_CURRENT_SOURCE_DIR}/") does not work
because cmake seems to strip the trailing slash.

Also relax the cmake version requirement from 3.12 to 3.9 as everywhere
else in the tree: it works just fine.