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.
* dwarf2read.c (struct dwarf2_cu): New field producer_is_gcc_lt_4_3.
Update the comment for checked_producer.
(check_producer): New forward declaration.
(producer_is_gcc_lt_4_3): New function.
(find_file_and_directory): Simulate *COMP_DIR only for gcc < 4.3.
(check_producer): Initialize also PRODUCER_IS_GCC_LT_4_3.
gdb/testsuite/
* gdb.dwarf2/dw2-compdir-oldgcc.S: New file.
* gdb.dwarf2/dw2-compdir-oldgcc.exp: New file.