Fix building for MacOSX

- Add a new macro named IS_MACOSX to hwaccess.c and use it to enable iopl().
  This was broken since r1638. This fix does *not* restore the very permissive
  concept where iopl() was activated in an #else branch that was inplace before
  r1638.
- Make printing the image file's size in flashrom.c platform independent.

Bonus: remove definitions of off64_t and lseek64 which are not necessary
anymore for about 1000 commits.

Thanks to SJ for reporting the issue and testing the solution.

Corresponding to flashrom svn r1648.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/flashrom.c b/flashrom.c
index d89860a..e1be398 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -1121,8 +1121,8 @@
 		return 1;
 	}
 	if (image_stat.st_size != size) {
-		msg_gerr("Error: Image size (%ld B) doesn't match the flash chip's size (%ld B)!\n",
-			 image_stat.st_size, size);
+		msg_gerr("Error: Image size (%jd B) doesn't match the flash chip's size (%ld B)!\n",
+			 (intmax_t)image_stat.st_size, size);
 		fclose(image);
 		return 1;
 	}