Ability to get full path of File object

[alex-tee]

when you have this

my_files = files(['myfile1.scm', 'myfile2.scm'])

you should be able to do this

foreach f : my_files
  message (f.full_path())
endforeach

so you can reuse those paths elsewhere

[viric]

full path or even the path relative to the src root. The object could have multiple methods.

[tristan957]

I started work on a PR to implement this fyi :). If there are other methods you would find useful, please comment in the PR, so we can get some discussion going.

[bruchar1]

Fixed in #12408.