There are two useful macros that can be defined before including
glib.h that are related to the min required glib version

 - GLIB_VERSION_MIN_REQUIRED

   When this is defined, if code uses an API that was deprecated
   in this version, or older, a compiler warning will be emitted.
   This alerts maintainers to update their code to whatever new
   replacement API is now recommended best practice.

 - GLIB_VERSION_MAX_ALLOWED

   When this is defined, if code uses an API that was introduced
   in a version that is newer than the declared version, a compiler
   warning will be emitted. This alerts maintainers if new code
   accidentally uses functionality that won't be available on some
   supported platforms.

The GLIB_VERSION_MAX_ALLOWED constant makes it a bit harder to opt
in to using specific new APIs with a GLIB_CHECK_VERSION conditional.
To workaround this Pragmas can be used to temporarily turn off the
-Wdeprecated-declarations compiler warning, while a static inline
compat function is implemented. This workaround is illustrated with the
implementation of the g_strv_contains method to satisfy the test suite.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>