Delete the gdb/osf-share directory.

Delete the gdb/osf-share directory.

These are old files that GDB does not use anymore, and probably has not
used for a long time.

gdb/ChangeLog:

        * osf-share/AT386/cma_thread_io.h: Delete.
        * osf-share/HP800/cma_thread_io.h: Delete.
        * osf-share/README: Delete.
        * osf-share/RIOS/cma_thread_io.h: Delete.
        * osf-share/cma_attr.h: Delete.
        * osf-share/cma_deb_core.h: Delete.
        * osf-share/cma_debug_client.h: Delete.
        * osf-share/cma_errors.h: Delete.
        * osf-share/cma_handle.h: Delete.
        * osf-share/cma_init.h: Delete.
        * osf-share/cma_list.h: Delete.
        * osf-share/cma_mutex.h: Delete.
        * osf-share/cma_sched.h: Delete.
        * osf-share/cma_semaphore_defs.h: Delete.
        * osf-share/cma_sequence.h: Delete.
        * osf-share/cma_stack.h: Delete.
        * osf-share/cma_stack_int.h: Delete.
        * osf-share/cma_tcb_defs.h: Delete.
        * osf-share/cma_util.h: Delete.
        * Makefile.in (HFILES_NO_SRCDIR): Remove entries for the files
        in osf-share.
        * config/djgpp/fnchange.lst: Remove osf-share/cma_stack_int.h entry.
        * contrib/ari/gdb_find.sh: Remove handling of osf-share.
        * copyright.sh (NOT_FSF_LIST): Remove "gdb/osf-share" entry.