DWARF-5: Macros
    
    DWARF-5 renamed DW_MACRO_GNU_* to DW_MACRO_*.
    
    gdb/ChangeLog
    2017-02-20  Jan Kratochvil  <jan.kratochvil@redhat.com>
    
    	* dwarf2read.c (read_file_scope): Rename DW_MACRO_GNU_*.
    	(dwarf_parse_macro_header): Accept DWARF version 5.
    	(dwarf_decode_macro_bytes, dwarf_decode_macros): Rename DW_MACRO_GNU_*.