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