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