* symtab.h (enum namespace): Add new namespaces FUNCTIONS_NAMESPACE,

    * symtab.h (enum namespace): Add new namespaces FUNCTIONS_NAMESPACE,
        TYPES_NAMESPACE, METHODS_NAMESPACE, and VARIABLES_NAMESPACE used by
        new search_symbols.
        Add prototype for search_symbols and free_search_symbols.

        * symtab.c (list_symbols): Rewrite to use new search_symbols.
        (file_matches): New helper function for search_symbols.
        (free_search_symbols): New function which frees data returned from
        search_symbols.
        (print_symbol_info): New helper function which prints info about a
        matched symbol to stdout. Extracted from old list_symbols.
        (print_msymbol_info): New helper function which prints info about
        a matched msymbol to stdout. Extracted from old list_symbols.
        (symtab_symbol_info): Extracted from old list_symbols.
        (variables_info): Use symtab_symbol_info.
        (functions_info): Use symtab_symbol_info.
        (types_info): Use symtab_symbol_info.
        (rbreak_command): Rewrite to use new search_symbols.

        * gdbtk.c: Change all references to static global "interp" to
        "gdbtk_interp" and export this global.
        (gdbtk_init): If gdbtk_source_filename is not NULL, source this file
        into the interpreter when it goes idle.
        Add new command "gdb_search".
        (gdb_search): New function which searches the symbol table.
        (gdbtk_test): New function called by main when the --tclcommand
        option is used.

        * main.c (main): Add a new option "--tclcommand" which is used
        by the testsuite to source a file into the interpreter when it
        goes idle.