Index: test/lit.common.cfg
===================================================================
--- test/lit.common.cfg
+++ test/lit.common.cfg
@@ -61,7 +61,8 @@
 config.environment['PATH'] = path
 
 # Help MSVS link.exe find the standard libraries.
-if platform.system() == 'Windows':
+# Make sure we only try to use it when targetting Windows
+if platform.system() == 'Windows' and config.target_triple.endswith('win32'):
   config.environment['LIB'] = os.environ['LIB']
 
 # Use ugly construction to explicitly prohibit "clang", "clang++" etc.