Closes #28 github issue.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

$(builddir) is always ., except apparently on automake 1.9 which
doesn’t define it.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

[andersk@mit.edu: Move code to new third/libstddjb directory]

Use selfpipe in our client, server, and examples.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

environ doesn’t work on OS X.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

[seph@directionless.org, andersk@mit.edu: add in even more places]

Add mach_absolute_time and gettimeofday timestamp implementations, and
fix clock_gettime check so that it can actually succeed

On most systems, even if __STDC_ISO_10646__ is not declared, wchar_t
will be correct in a UTF-8 locale. The client and server both enforce
a locale check on startup.

[andersk@mit.edu: Add byteorder.h to libmoshcrypto_a_SOURCES]

With automake 1.11, this gives us Linux kernel–style silent output
that makes warnings more obvious:

  GEN    userinput.pb.cc
  CXX    userinput.pb.o
  AR     libmoshprotos.a
  CXXLD  mosh-client

(Use ‘make V=1’ for the traditional verbose output.)

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

This turns off -Werror by default except in the Debian package.
-Werror is inherently unportable and breaks things on OS X.  While it
can cause problems in Debian too, this is at least a little better.

It also turns off -pedantic in src/protobufs, because apparently
protoc output doesn’t compile with -pedantic on all platforms.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>