Also changing libs + lib_dirs in gof/cmodule.py for consistency.

theano/gof/cmodule.py

@@ -2122,8 +2122,8 @@ class GCC_compiler(Compiler):
             preargs = list(preargs)
 
         include_dirs = include_dirs + std_include_dirs()
-        libs = std_libs() + libs
-        lib_dirs = std_lib_dirs() + lib_dirs
+        libs = libs + std_libs()
+        lib_dirs = lib_dirs + std_lib_dirs()
 
         cppfilename = os.path.join(location, 'mod.cpp')
         with open(cppfilename, 'w') as cppfile: