(ssize_t, pid_t) [_WIN32]: Back out the previous revision of unistd.h

and move to w32misc.h instead.  Belong into sys/types.h but we can't
fix system headers.

src/lib/w32/unistd.h

@@ -38,9 +38,6 @@
 #include "getopt.h"
 #include <sys/stat.h>
 
-typedef long ssize_t;
-typedef int pid_t;
-
 /*
  * posixfile.c
  */

src/lib/w32/w32misc.h

@@ -47,6 +47,9 @@
 #define random rand
 #define srandom srand
 
+typedef long ssize_t;
+typedef int pid_t;
+
 /*
  * strptime.c
  */