making your own *.lib. Which flag to use (-ms or -mf)? (+)

I want to make a library for the later use with all other projects.
Let’s use zlib-1.2.1 as an example.

I need two versions of the library - register and stack.
So, I compile it with -4r and -4s respectively.
This will give me zlib3r.lib and zlib3s.lib respectively. I’ll symlink them to /usr/lib.

But which of -mf/-ms flag should I use to not have problems with any other project, be it compiled with either flag itself?

OK, I’ve got the answer on (qnx.qnx4 thread).

The correct way of making libraries is -ms flag.