search for: __mingw32

I'm trying to link against libvorbis.a using GnuWin32 without the Cygwin layer (that is, Mingw32). Unfortunately the linker complains about a missing function: rint(). This function is used a couple of times in libvorbis and as far as I understand this is a standard C library function. My problem is, that I cannot find rint() in any of the common DLLs nor do I know how MSVC resolves this