Remove hardcoded compilation flags

Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -25,7 +25,7 @@ else()
     set(LIBSUFFIX "")
 endif()
 
-add_definitions( -Wall -O3 -g -Wno-pointer-sign -fPIC -std=gnu99)
+add_definitions( -Wall -Wno-pointer-sign -fPIC -std=gnu99)
 # add_definitions(  -Wall -O0 -g -Wno-pointer-sign )
 
 ### ORC is not used in any active code at the moment  ###