Windows replacement for strtok_r()

They spell it "strtok_s" there.

There are currently no uses, but some will be added soon.

Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: David Steele <david@pgmasters.net>
Discussion: https://www.postgresql.org/message-id/flat/79692bf9-17d3-41e6-b9c9-fc8c3944222a@eisentraut.org

Author: petere

src/include/port/win32_port.h

@@ -415,6 +415,11 @@ extern int	_pglstat64(const char *name, struct stat *buf);
 #undef ETIMEDOUT
 #define ETIMEDOUT WSAETIMEDOUT
 
+/*
+ * Supplement to <string.h>.
+ */
+#define strtok_r strtok_s
+
 /*
  * Locale stuff.
  *