How can a static release lib be linked into a debug build?

Question

The Gameplay Project distributes a set of static libraries of all it's dependencies. The libraries they include will link in a debug or release build of an application. I ran the strings command on their lib and compared it to one I compiled. The linker directive /FAILIFMISMATCH:"RuntimeLibrary=MD_DynamicRelease" is set in my library, but not theirs.

How did they compile their library this way?

Edit: Clarification

I failed to mention that this occurs on the next branch, which uses libs compiled for VS2012. The _MSC_VER of the libraries is 1700.

I am aware that you shouldn't link different versions of the CRT, but I'm wondering how they were even able to compile it this way.

Answer 1

It seems MS has started adding /FAILIFMISMATCH:"RuntimeLibrary line from vs2012. /FAILIFMISMATCH itself is introduced in vs2010. I've chekced Gameplay Project sln file and it is using vs2010. Try to use vs2010 and see if the directive is gone.

I think you already know this but it doesn't really matter if the directive is there or not because you must match the runtime library compile option anyway.