Some programs that use the Python C API have difficulties finding
cross-compiled Python3 without the pkgconfig, so make sure we have
python3.pc and python-3.7.pc in pkgconfig staging dir.
CircleCI requires a package Makefile change to actually
do the CI check, so bump PKG_RELEASE.
Signed-off-by: Daniel F. Dickinson <cshored@thecshore.com>