* Makefile.in (symfile-mem.o): Update dependencies.
* i386-linux-tdep.c (i386_linux_dwarf_signal_frame_p): New.
(i386_linux_init_abi): Call dwarf2_frame_set_signal_frame_p.
* inf-ptrace.c (inf_ptrace_attach): Call
observer_notify_inferior_created.
* inftarg.c (child_attach): Likewise.
* symfile-mem.c: Include "observer.h", "auxv.h", and "elf/common.h".
(symbol_file_add_from_memory): Take NAME argument. Use it for
the new BFD's filename.
(add_symbol_file_from_memory_command): Update call to
symbol_file_add_from_memory.
(struct symbol_file_add_from_memory_args, add_vsyscall_page)
(symbol_file_add_from_memory_wrapper): New.
(_initialize_symfile_mem): Register add_vsyscall_page as an
inferior_created observer.