meson: Allow building of g-i with static libs.

Allow building of g-i with static libs which should
work since Meson 0.49 and sufficiently recent
gobject-introspection (>= 1.58.1). If g-i is too
old people will get a suitable error message and
can disable g-i via build options.
2 jobs for meson-allow--gir-with-static-lib in 4 minutes and 5 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #69149
build autotools

00:01:01

passed #69150
build meson

00:04:02