CFLAGS and LDFLAGS were unused. We are now defining them in LOC, using
the definition of CFLAGS and LDFLAGS from rbm.conf.

We also don't hardcode anymore -j4.

This reverts commit b8bae588, reversing
changes made to 42720c51.

It turns out this binutils update is causing non-reproducible outomces.
We need to investigate those further in #16472.

Fix the build of openssl and zlib for Windows 64.