auto merge of #10346 : klutzy/rust/mingw64-32-fix, r=alexcrichton

Fixes #10327

src/etc/mingw-fix-include/winsock2.h

@@ -3,6 +3,9 @@
 
 #include_next <winsock2.h>
 
+// mingw 4.0.x has broken headers (#9246) but mingw-w64 does not.
+#if defined(__MINGW_MAJOR_VERSION) && __MINGW_MAJOR_VERSION == 4
+
 typedef struct pollfd {
   SOCKET fd;
   short  events;
@@ -10,3 +13,5 @@ typedef struct pollfd {
 } WSAPOLLFD, *PWSAPOLLFD, *LPWSAPOLLFD;
 
 #endif
+
+#endif // _FIX_WINSOCK2_H