Try to fix Google config

Author: mcbarton

cmake/modules/GoogleTest.cmake

@@ -38,7 +38,7 @@ ExternalProject_Add(
   # CMAKE_ARGS -DCMAKE_ARCHIVE_OUTPUT_DIRECTORY_DEBUG:PATH=DebugLibs
   #            -DCMAKE_ARCHIVE_OUTPUT_DIRECTORY_RELEASE:PATH=ReleaseLibs
   #            -Dgtest_force_shared_crt=ON
-  CONFIGURE_COMMAND ${config_cmd}
+  CONFIGURE_COMMAND ${config_cmd} -G ${CMAKE_GENERATOR}
                 -DCMAKE_BUILD_TYPE=$<CONFIG>
                 -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
                 -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}