[PATCH 0/4] gas: Dwarf generation adjustments

[Jan Beulich]

While working on the partial (see there) fix contained in patch 1 I've
noticed a few more things which the remaining patches here attempt to
improve.

1: Dwarf: improve debug info generation from .irp and alike blocks
2: Dwarf5: drop dead code
3: Dwarf5: adjust .debug_line file 0 checking
4: Dwarf5: re-use file 0 line string table entry when faking file 0

Jan