Rename module termios to termios-h. * modules/termios-h: Renamed from modules/termios. * modules/termios-h-tests: Renamed from modules/termios-tests. * modules/termios-h-c++-tests: Renamed from modules/termios-c++-tests. * tests/test-termios-h.c: Renamed from tests/test-termios.c. * tests/test-termios-h-c++.cc: Renamed from tests/test-termios-c++.cc. * doc/posix-headers/termios.texi: Update. * modules/* (Depends-on): Update. * modules/termios: New file.