Oooops. Forgot to add no sysmon flag for release builds (this new optout feature segfaults).

Author: ionelmc

setup.py

@@ -30,7 +30,7 @@
     CFLAGS = os.environ['CFLAGS'] = '-DCYTHON_TRACE=1 -DCYTHON_USE_SYS_MONITORING=0'
     LFLAGS = os.environ['LFLAGS'] = ''
 else:
-    CFLAGS = ''
+    CFLAGS = '-DCYTHON_USE_SYS_MONITORING=0'
     LFLAGS = ''
 
 allow_extensions = True