Ada, treelang needs to be converted to --enable-mapped-location

[Robert Dewar]

Richard Kenner wrote:
>     Are you thinking of some other file?  sinfo.ad[sb] barely mentions
>     Source_Ptr at all:  Only in two functions to get/set the End_Span,
>     neither of looks like they would need to be changed when converting
>     to source_location!
> 
> Sorry, indeed I was: sinput.ad[bs].
> 
>     The gain is that alternative solutions require mapping between two
>     encodings for source locations.  Plus better integration between Ada
>     and the rest of the compilers, which *we* think is desirable.  Plus
>     using source_location is probably faster, considering what you have to
>     go through in Sloc_to_locus (even *before* switching to
>     source_location.

Sloc's are used to convey semantic information, in particular they are
used to determine unit membership, and source position, so you need to
look at lib.adb as well.