erlang: Adding Erlang/OTP 17.3.

This one was a bit annoying. Walking through the patch, we have:

* hipe_x86_signal.c checks for GLIBC, fails and falls through to a mostly generic branch intended for Solaris that specifies a non-existent _sigaction (musl has __sigaction) and a redefinition of _NSIG that needs to be clipped.
* erl_poll.h uses __uint32_t. For shame.
* ei_resolve.c also checks for GLIBC, fails and falls through to an invalid gethostbyname_r call.
* install_bin assumes that --prefix passed to configure will never be empty, as exec_prefix will default to --prefix if not explicitly specified. It then checks if exec_prefix is empty and will fail. We pass --prefix="$butch_prefix" to configure, which typically is empty and causes an install failure. Removing the check works just fine.