setup: Compile loop.c with -O2

Author: 1st1

setup.py

@@ -106,7 +106,8 @@ def build_extensions(self):
             "uvloop.loop",
             sources=[
                 "uvloop/loop.c",
-            ]
+            ],
+            extra_compile_args=['-O2']
         ),
     ],
     classifiers=[