MFH: r552393
deskutils/gnome-contacts: fix build on GCC architectures
Use C11 compiler:
In file included from /usr/local/include/libhandy-1/handy.h:50,
from src/gnome-contacts.p/contacts-addressbook-dialog.c:26:
/usr/local/include/libhandy-1/hdy-swipe-tracker.h:23: error: redefinition of typedef 'HdySwipeTracker'
/usr/local/include/libhandy-1/hdy-types.h:15: error: previous declaration of 'HdySwipeTracker' was here
Approved by: portmgr (fix build blanket)