* gdbarch.sh (find_memory_regions): New callback.

	* gdbarch.sh (find_memory_regions): New callback.
	* gdbarch.c, gdbarch.h: Regenerate.

	* gcore.c (gcore_memory_sections): Try gdbarch find_memory_regions
	callback before falling back to target method.

	* linux-nat.c (read_mapping, linux_nat_find_memory_regions): Remove.
	(linux_target_install_ops): No longer install it.

	* linux-tdep.c (linux_find_memory_regions): New function.
	(linux_init_abi): Install it.