This splits the eolian_file_parse API into two, one for parsing
files already present in the database (always by filename) and
one for parsing paths.
It fixes several bugs/leaks on the way (incorrect use of
stringshare etc.) as well as adds checking for whether there
are no conflicting filenames at scan time, for free. That means
it is now no longer possible to scan two paths which have an eo
or eot file of the same name in them.
It should also be faster now.
It also fixes T7820.
@fix
Having these files would result in eolian cxx tests failing when
building using autotools, as eolian generators by default include
entire src directory and eolian cxx already had classes a/b/c.
In an ideal case this should not happen as eolian cxx should not
scan tests that are not its own, and it already behaves correctly
under meson but there is no good way to fix it for autotools, so
just rename as a workaround.
Daniel Kolesa