meson: Fix deprecation warning for pkgconfig

Meson 0.49 now issues a warning for libraries being passed into the
'libraries' keyword argument. Now they should be passed as a positional
argument.

See
https://mesonbuild.com/Release-notes-for-0-49-0.html#deprecation-warning-in-pkgconfig-generator



Signed-off-by: Scott Anderson <scott.anderson@collabora.com>