Apple provides a non-standard (and by-default disabled) -Wnewline-eof in
both clang, and Apple's port of GCC.
Some PLCrashRpoerter users have this option turned on in their builds,
causing build failures in cases where our headers do not contain
terminating newlines.
To improve compatibility for users issues going forward, this commit
enables -Wnewline-eof and fixes all files missing terminating newlines.
Mikhail Suendukov
Anastasia Kubova
Dmitrii Chichuk
Landon Fuller
Landon Fuller