gdbserver build-id attribute generator

gdbserver build-id attribute generator

Producer part of the new "build-id" XML attribute.

gdb/ChangeLog
2015-07-15  Aleksandar Ristovski  <aristovski@qnx.com
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	gdbserver build-id attribute generator.
	* features/library-list-svr4.dtd (library-list-svr4): New
	'build-id' attribute.

gdb/doc/ChangeLog
2015-07-15  Aleksandar Ristovski  <aristovski@qnx.com
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	gdbserver build-id attribute generator.
	* gdb.texinfo (Library List Format for SVR4 Targets): Add
	'build-id' in description, example, new attribute in dtd.

gdb/gdbserver/ChangeLog
2015-07-15  Aleksandar Ristovski  <aristovski@qnx.com
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	gdbserver build-id attribute generator.
	* linux-low.c (nat/linux-maps.h, search.h, rsp-low.h): Include.
	(ElfXX_Ehdr, ElfXX_Phdr, ElfXX_Nhdr): New.
	(ELFXX_FLD, ELFXX_SIZEOF, ELFXX_ROUNDUP, BUILD_ID_INVALID): New.
	(find_phdr): New.
	(get_dynamic): Use find_pdhr to traverse program headers.
	(struct mapping_entry, mapping_entry_s, free_mapping_entry_vec)
	(compare_mapping_entry_range, struct find_memory_region_callback_data)
	(read_build_id, find_memory_region_callback, lrfind_mapping_entry)
	(get_hex_build_id): New.
	(linux_qxfer_libraries_svr4): Add optional build-id attribute
	to reply XML document.