Fix for Python 3.13: explicitly include unistd.h

Author: hugovk

src/libImaging/TiffDecode.c

@@ -12,6 +12,10 @@
 
 #include "Imaging.h"
 
+#ifndef _UNISTD_H
+#include <unistd.h> /* lseek */
+#endif
+
 #ifdef HAVE_LIBTIFF
 
 #ifndef uint

src/libImaging/TiffDecode.h

@@ -13,12 +13,6 @@
 #include <tiff.h>
 #endif
 
-/* UNDONE -- what are we using from this? */
-/*#ifndef _UNISTD_H
-  # include <unistd.h>
-  # endif
-*/
-
 #ifndef min
 #define min(x, y) ((x > y) ? y : x)
 #define max(x, y) ((x < y) ? y : x)