roadmap: describe glibc commands.

Some glibc commands are irrelevant because they're for functionality
that is excluded from musl (mtrace, rpc*, localedef, iconvconfig, nscd).
getconf and catchsegv look like candidates for the development toolchain;
locale and iconv were already triaged.
getent is pretty lame, but it and the timezone stuff (tzselect zic
zdump) are the only new possibly interesting commands.
On further analysis, none of the glibc commands are interesting.
getty: build fix, clean up messages, simplify code

build fix: xmsprintf has been renamed
shorten and lowercase the error messages
use xexec() instead of execlp(); perror_exit();
remove redundant variable setting
iconv is actually something I'm missing on my current musl based system.
Attached is a simple version using the libc's iconv.
iconv cleanup.
An implementation of __printf__ is attached.
An issue in ifconfig while verifying the HW Address, which is assumed to be of the format __C2:79:38:95:CD:AB__ but can be of form __C2:79:38:95:D:A__. In this case the HW address is reported as bad.
A tool to reset the terminal.
This implementation depends on the _stty_ 'sane' settings.
Probes for O_NOFOLLOW that compile and run something aren't compatible with cross compiling, so just #define it to 0 if it's not in fcntl.h where posix-2008 says.
Probe for the existence of FIFREEZE and make fsfreeze depend on it.
Revert lots of half-finished local debris I didn't mean to check in with Isaac's roadmap update.

Mercurial's "import" command is still broken, committing local tree changes to files that weren't even touched by the patch because the hg developers inisist, when I point out how stupid it is, that they meant to do that. (hg record can do hunks, but import can't even track _files_.)
This version of fold fixes major bugs (infinite loop, overflow) and adds an option for un/refolding text.