* All GDB files that #include defs.h: Removed stdio.h.
(defs.h): #include stdio.h.
This has been tested by building GDBs for all targets hosted on Sun4.
None of the build problems were related to stdio.h inclusion. (n.b.
many configurations don't build for other reasons.)
* breakpoint.c (breakpoint_re_set): Use ALL_BREAKPOINTS_SAFE.
* symtab.c (find_pc_symtab): Handle having no objfiles.
* infcmd.c: Fix comment.
* objfiles.c (free_all_objfiles): Add.
* symfile.h (ALL_OBJFILES, ALL_OBJFILES_SAFE): Add.
* symfile.c (symbol_file_command): free all objfiles when
specifying a new symbol file.
(reread_symbols): Stat the file name, don't fstat the descriptor.
