GENERATED files can be used as dependencies for other targets, so it's
misguided (at best) to filter them with a blunt whitelist.
However, there does exist an extension that needs to be skipped: on Windows +
MSVC, CMake will by default try to generate a Visual Studio project, and
there dependencies with no inputs are instead tied to a dummy .rule
input file which is created by the generation step. The fileapi will
still report those, so it will cause Meson to bail out when it realises
there's no such file in the build tree.
Fixes#11607
This PR refactors the old output_target_map, which was a
raw dict, into it's own class. This makes the access to
the map more uniform and robust (at the cost of more lines
of code).
Additionally relative paths to the build directory are
now also tracked for outputs. This is neccessary to
corretcly distingluish files with the same name, that are
in different directories.
L. E. Segovia