libexif: Avoid buffer overflow due to compiler optimization am: ba7f703b28 am: 62e2456a62 am: 9fb8525139 am: 3a1598c9e0 am: de95d0ccc0

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/libexif/+/12828416

Change-Id: I6ab35753ca93396743215595ae3b11f364414eef