With it, we can remove the two sole tests of HAVE_TERMIOS_H.
* bootstrap.conf (gnulib_modules): Add termios.
* src/ls.c: Don't test HAVE_TERMIOS_H.
* src/stty.c: Likewise.
* m4/jm-macros.m4 (gl_CHECK_ALL_TYPES): Remove configure-time
test for termios.h.