[Dwarf-discuss] Proposal: add DW_AT_lower_bound to DW_TAG_string_type

[Martin]

# Proposal to add DW_AT_lower_bound to DW_TAG_string_type

## Background

Pascal normally use 1-based indexes for strings. But it can also 
generate strings with a 0-based index.

Other languages may have varying defaults.

For a debugger to show the result of an expression like
   `MyString[5]`
the start value of the index is needed.


## Proposed Changes

1. Allow DW_AT_lower_bound as an attribute in DW_TAG_string_type.

2. Define a list of language specific defaults (as exists for subrange 
low bounds)

The default for DW_LANG_Pascal83 should be `1`

## References

http://docwiki.embarcadero.com/RADStudio/Athens/en/Zero-based_strings_(Delphi)
Also supported by FreePascal