Use SSIZE_T and SSIZE_T_MAX

Author: derobins

src/H5private.h

@@ -371,7 +371,7 @@
  * Only needed where ssize_t isn't a thing (e.g., Windows)
  */
 #ifndef SSIZE_MAX
-#define SSIZE_MAX PTRDIFF_MAX
+#define SSIZE_MAX SSIZE_T_MAX
 #endif
 
 /*

src/H5public.h

@@ -290,7 +290,7 @@ typedef int htri_t;
  * Use of ssize_t should be discouraged in new code.
  */
 #ifdef _WIN32
-typedef ptrdiff_t ssize_t;
+typedef SSIZE_T ssize_t;
 /* This will have been defined to 0 in configure */
 #define H5_SIZEOF_SSIZE_T H5_SIZEOF_SIZE_T
 #endif