[Doc] libopenmpt: Document MinGW-w64 mcfgthread threading model as su…

…pported.

git-svn-id: https://source.openmpt.org/svn/openmpt/branches/OpenMPT-1.31@20659 56274372-70c3-4bfc-bfc3-4c3a0b034d27

doc/libopenmpt/dependencies.md

@@ -24,7 +24,7 @@ Dependencies
      *  **GCC 7.1** or higher
      *  **Clang 6** or higher
      *  **MinGW-W64 7.1** or higher (it is recommended to preferably use
-        posix threading model as opposed to win32 threading model)
+        mcfgthread or posix threading model as opposed to win32 threading model)
      *  **emscripten 3.1.1** or higher
      *  **DJGPP GCC 7.1** or higher
      *  any other **C++20 or C++17 compliant** compiler