This commit updates the backport from grilo-plugins master to include
a symbol name change.

Changes to libdmapsharing modified IS_X_... symbols to read X_IS_....
This was adopted in grilo-plugins master, as there was no official release
of grilo-plugins since adding support for libdmapsharing4 in the first
place. The next release of grilo-plugins will be the first to include
libdmapsharing4 support to include the X_IS_... name change.

Fixes issue mentioned at #12766.

Signed-off-by: W. Michael Petullo <mike@flyn.org>