Warnings at configure time with Meson 0.47.0 and later
Meson 0.47.0 has introduced the following warning:
src/tracker-extract/meson.build:135: WARNING: Got an empty configuration_data() object and found no substitutions in the input file '10-bmp.rule'. If you want to copy a file to the build dir, use the 'copy:' keyword argument added in 0.47.0 Configuring 10-comics.rule using configuration
We could fix by doing what the message says but we would have to depend on Meson 0.47.0 which might be painful for some distributors. Maybe we should leave with the warnings until Meson 0.47.0 is in some stable distro releases...