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