Index: llvm/trunk/cmake/modules/GetHostTriple.cmake
===================================================================
--- llvm/trunk/cmake/modules/GetHostTriple.cmake
+++ llvm/trunk/cmake/modules/GetHostTriple.cmake
@@ -15,7 +15,7 @@
       set( value "i686-pc-windows-gnu" )
     endif()
   else( MSVC )
-    if(CMAKE_HOST_SYSTEM_NAME STREQUAL Windows)
+    if(CMAKE_HOST_SYSTEM_NAME STREQUAL Windows AND NOT MSYS)
       message(WARNING "unable to determine host target triple")
     else()
       set(config_guess ${LLVM_MAIN_SRC_DIR}/cmake/config.guess)