Update libgsm to patchlevel 16.

No real changes to the files we use. (Seems like contrary to README.version
we were already past patchlevel 13).

Also stop suppressing warnings about undefined behavior. Lying to ourselves
doesn't seem useful.

Bug: N/A
Test: builds
Change-Id: I9090720f6902e38a769405200700330951756b07
40 files changed