Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -117,7 +117,7 @@ if (MSVC)
     add_compile_options(/W4)
 else()
     # additional warnings
-    add_compile_options(-Wall -fPIC -O3)
+    add_compile_options(-Wall -fPIC)
 endif()
 
 if (ENABLE_STRICT)
