win: Move NTDDI_VERSION into winver, stop setting it for usrsctp

third_party/usrsctp/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 config("usrsctp_config") {
   include_dirs = [
     "usrsctplib/usrsctplib",
     "usrsctplib/usrsctplib/netinet",
   ]
 }
@@ skipping 105 matching lines @@
     defines += [
       "HAVE_SA_LEN",
       "HAVE_SCONN_LEN",
       "__APPLE_USE_RFC_2292",
       "__Userspace_os_Darwin",
     ]
     cflags += [ "-U__APPLE__" ]
   }
 
   if (is_win) {
-    defines += [
-      "__Userspace_os_Windows",
-
-      # Manually setting WINVER and _WIN32_WINNT is needed because Chrome
-      # sets WINVER to a newer version of  windows. But compiling usrsctp
-      # this way would is incompatible  with windows XP.
-      "WINVER=0x0502",
-      "_WIN32_WINNT=0x0502",
-    ]
-    configs -= [ "//build/config/win:winver" ]
+    defines += [ "__Userspace_os_Windows" ]
   } else {
     defines += [ "NON_WINDOWS_DEFINE" ]
   }
 
   deps = [
     "//third_party/boringssl",
   ]
 }