... instead of requiring progname to be used (or program_name to be
provided).
* lib/argmatch.c: Do not include progname.h.
[TEST] (program_name): Do not define.
[TEST] (main): Call getprogname instead of using program_name.
* lib/c-stack.c: Do not include progname.h.
(program_name): Do not define.
(die): Call getprogname instead of using program_name.
* lib/chdir-long.c: Do not include progname.h.
[TEST_CHDIR] (main): Do not set program_name.
* lib/error.c [!_LIBC]: Include progname.h.
[!_LIBC] (program_name): Define using getprogname.
* lib/euidaccess.c: Do not include progname.h.
[TEST] (main): Do not set program_name.
* lib/git-merge-changelog.c: Include getprogname.h instead of
progname.h.
(usage): Call getprogname instead of using program_name.
(main): Likewise. Stop calling set_program_name.
* lib/group-member.c: Do not include progname.h.
[TEST] (main): Do not set program_name.
* modules/argmatch (Depends-on): Add getprogname.
* modules/c-stack (Depends-on): Likewise.
* modules/error (Depends-on): Likewise.
* modules/git-merge-changelog (Depends-on): Likewise.
Also remove progname.