bpo-37731: Reorder includes in xmltok.c to avoid redefinition of _POSIX_C_SOURCE (pythonGH-16733)

Author: pablogsal

Modules/expat/xmltok.c

@@ -30,6 +30,14 @@
    USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+#ifdef _WIN32
+#  include "winconfig.h"
+#else
+#  ifdef HAVE_EXPAT_CONFIG_H
+#    include <expat_config.h>
+#  endif
+#endif /* ndef _WIN32 */
+
 #include <stddef.h>
 #include <string.h> /* memcpy */
 
@@ -42,14 +50,6 @@
 #  include <stdbool.h>
 #endif
 
-#ifdef _WIN32
-#  include "winconfig.h"
-#else
-#  ifdef HAVE_EXPAT_CONFIG_H
-#    include <expat_config.h>
-#  endif
-#endif /* ndef _WIN32 */
-
 #include "expat_external.h"
 #include "internal.h"
 #include "xmltok.h"