diff --git a/.waf-tools/cryptopp.py b/.waf-tools/cryptopp.py
index 8244d53..93abd84 100644
--- a/.waf-tools/cryptopp.py
+++ b/.waf-tools/cryptopp.py
@@ -101,7 +101,7 @@
         self.fatal('CryptoPP not found or is not usable')
 
     isLibWorking = False
-    for defines in ['', 'CRYPTOPP_DISABLE_ASM']:
+    for defines in [[], ['CRYPTOPP_DISABLE_ASM']]:
         try:
             self.check_cxx(msg='Checking if CryptoPP library works',
                            fragment=CRYPTOPP_CHECK_FRAGMENT,