Reverting pid_t type change (this was breaking code that considers pid_t as signed)

Author: manojampalam

contrib/win32/win32compat/inc/defs.h

@@ -70,7 +70,9 @@ typedef int sigset_t;
 
 typedef unsigned short _mode_t;
 typedef _mode_t mode_t;
-typedef DWORD_PTR pid_t;
+/* TODO - investigate if it makes sense to make pid_t a DWORD_PTR. 
+ * Double check usage of pid_t as int */
+typedef int pid_t;
 
 /* wait pid options */
 #define WNOHANG 1