Update support for GNU BUILD notes so that version notes can contain extra information, and stack protection notes can contain numeric values.

	* readelf.c (print_gnu_build_attribute_name): Allow stack
	protection notes to contain numeric values.  Use a colon rather
	than a space to separate a string name from its values.  Decode
	the numeric value of a stack protection note.
	* objcopy.c (merge_gnu_build_notes): Allow version notes to
	contain extra text after the protocol version number.