Add type cast and fix increment

Adding type cast and fixing index increment, to enable building outside
of the stack_unwinder DFM, where these are currently causing build
failures.

Bug:375463618
Change-Id: I9a2fde1f6d69dea1a47b31875939ed65b40f886c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/third_party/libunwindstack/+/5994571
Reviewed-by: Mike Wittman <wittman@chromium.org>
Reviewed-by: Rodney Ding <rodneyding@google.com>
4 files changed