--- a/setup.py
+++ b/setup.py
@@ -25,7 +25,7 @@
 		build_args = ['--config', cfg,
 					  '-j', '8']
 
-		if platform.system() == "Windows":
+		if platform.system() == "Windows" and "MSC" in platform.python_compiler():
 			cmake_args += ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{}={}'.format(cfg.upper(), extdir)]
 			if sys.maxsize > 2**32:
 				cmake_args += ['-A', 'x64']