Fix _socket module compilation on Cygwin. (python#4137)

embray · serhiy-storchaka · commit 63ae04461fb0 · 2017-10-27T13:01:17.000+03:00
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
@@ -234,7 +234,7 @@ if_indextoname(index) -- return the corresponding interface name\n\
 # include <ctype.h>
 #endif
 
-#ifdef __APPLE__
+#if defined(__APPLE__) || defined(__CYGWIN__)
 # include <sys/ioctl.h>
 #endif
 
