meson and logging support

[Werner LEMBERG]

Meson experts,


please have a look at

  https://gitlab.freedesktop.org/freetype/freetype/-/merge_requests/46

Is this the right approach?  I'm not completely happy about the
message meson emits, and that the normal case (i.e., logging support
is disabled) is indicated with a red 'NO', which might people believe
there is an error:

  Header <freetype/config/ftoption.h> has symbol "FT_DEBUG_LOGGING" : NO

I guess the (better?) alternative is to write another auxiliary script
to parse `ftoption.h`, or to manually write a test that allows for a
more sensible message.

Thoughts?  Help is greatly appreciated :-)


    Werner