--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -40,7 +40,8 @@ set(CPACK_COMPONENT_STATICLIBS_GROUP "De
 set(CPACK_COMPONENT_HEADERS_GROUP    "Development")
 
 # Create suffix to eventually install in lib64
-IF(CMAKE_SIZEOF_VOID_P EQUAL 4)
+IF(DEFINED LIB_SUFFIX)
+  ELSEIF(CMAKE_SIZEOF_VOID_P EQUAL 4)
     SET(LIB_SUFFIX "")
     SET(PACK_ARCH "")
   ELSE(CMAKE_SIZEOF_VOID_P EQUAL 8)