Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
(read_common_block): Handle child DIEs with
DW_AT_data_member_location.
(new_symbol_full): Add special case for common blocks.
gdb/testsuite
* gdb.dwarf2/dw2-common-block.S: New file.
* gdb.dwarf2/dw2-common-block.exp: New file.