Enable x32 support in gdbserver

Enable x32 support in gdbserver

	* Makefile.in (clean): Also remove x32.c x32-linux.c
	x32-avx.c x32-avx-linux.c.
	(x32.o): New target.
	(x32.c): Likewise.
	(x32-linux.o): Likewise.
	(x32-linux.c): Likewise.
	(x32-avx.o): Likewise.
	(x32-avx.c): Likewise.
	(x32-avx-linux.o): Likewise.
	(x32-avx-linux.c): Likewise.

	* configure.srv (srv_amd64_regobj): Add x32.o x32-avx.o.
	(srv_amd64_linux_regobj): Add x32-linux.o x32-avx-linux.o.
	(srv_i386_64bit_xmlfiles): Add i386/x32-core.xml.
	(srv_amd64_xmlfiles): Add i386/x32.xml i386/x32-avx.xml.
	(srv_amd64_linux_xmlfiles): Add i386/x32-linux.xml
	i386/x32-avx-linux.xml.

	* linux-x86-low.c (init_registers_x32_linux): New prototype.
	(init_registers_x32_avx_linux): Likwise.
	(x86_linux_update_xmltarget): Call init_registers_x32_linux
	or init_registers_x32_avx_linux if linux_is_elf64 is false.