Comgr calls exit

[Mystro256]

Comgr calls exit, which is not advised.
To quote Fedora's rpmlint tool:

This library package calls exit() or _exit(), probably in a non-fork()
context. Doing so from a library is strongly discouraged - when a library
function calls exit(), it prevents the calling program from handling the
error, reporting it to the user, closing files properly, and cleaning up any
state that the program has. It is preferred for the library to return an
actual error code and let the calling program decide how to handle the
situation.

Thanks!

[lamb-j]

Currently we only call exit in comgr-objdump.cpp. This is left-over from copying code directly from the llvm-objdump implementation.

In the future we hope to resolve this by libraryizing llvm-objdump, which would allow llvm-objdump and comgr-objdump to call a shared API (and ideally that API doesn't call exit).