Makefile.nmake only builds Release configuration, resulting in mixed CRT warning in VS

[gh-andre]

Visual C++ expects different MSVC CRT options for Debug and Release builds and current Makefile.nmake builds only libraries for Release configurations. I realize that it's generated from tools/gen_nmake.mk and I didn't look into how it is plugged in for a PR, but if you are interested in a patch, in general, here's one for Makefile.nmake:

https://github.com/StoneStepsInc/isa-lib-crypto-nuget/blob/master/patches/01-nmake-debug-release.patch

With this patch, one can build Debug/Release libraries like this:

nmake -f Makefile.nmake CONFIG=DEBUG
nmake -f Makefile.nmake CONFIG=RELEASE