Unused variable/type nit from Thomas Adam.
Only set AUTO{MAKE,CONF}_VERSION on OpenBSD

OpenBSD requires the presence of AUTOMAKE_VERSION and AUTOCONF_VERSION for
bootstrapping purposes.  Setting these on any other system requires that
explicit version to be used, rather than what might already be installed.

Therefore, only do this when the platform is OpenBSD and ignore everything
else.
Don't set some string formats if the string is NULL.
Automatically reflow wrapped lines when a pane is resized, requested by
many over the years and finally implemented by Richard Woodbury.
Merge branch 'obsd-master'
Use osdep_get_cwd() for format change
Minor update to .gitignore

Now ignores:  corefiles, stray patches and tags file.
Add to TODO list.
Merge branch 'master' of ssh://git.code.sf.net/p/tmux/tmux-code