configure.ac contains gtk+-3.0 >= 3.12.0, yet compiling against such an older versions fails:

contacts-contact.o: In function `contacts_contact_presence_construct':
/home/michael/debian/build-area/gnome-contacts-3.16.2/src/contacts-contact.c:1208: undefined reference to `gtk_label_set_xalign'
contacts-contact-sheet.o: In function `contacts_contact_sheet_add_row_with_button':
/home/michael/debian/build-area/gnome-contacts-3.16.2/src/contacts-contact-sheet.c:306: undefined reference to `gtk_label_set_xalign'
contacts-contact-sheet.o: In function `contacts_contact_sheet_add_row_with_label':
/home/michael/debian/build-area/gnome-contacts-3.16.2/src/contacts-contact-sheet.c:399: undefined reference to `gtk_label_set_xalign'
/home/michael/debian/build-area/gnome-contacts-3.16.2/src/contacts-contact-sheet.c:411: undefined reference to `gtk_label_set_xalign'
contacts-contact-sheet.o: In function `contacts_contact_sheet_update':
/home/michael/debian/build-area/gnome-contacts-3.16.2/src/contacts-contact-sheet.c:803: undefined reference to `gtk_label_set_xalign'


gtk_label_set_xalign was introduced in 3.16, so the dependency should be bumped:

diff --git a/configure.ac b/configure.ac
index 01856d6..089391f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -37,7 +37,7 @@ AC_DEFINE_UNQUOTED([GETTEXT_PACKAGE], ["$GETTEXT_PACKAGE"], [Gettext Package])
 AC_SUBST(GETTEXT_PACKAGE)
 
 
-pkg_modules="gtk+-3.0 >= 3.12.0
+pkg_modules="gtk+-3.0 >= 3.16.0
             glib-2.0 >= 2.37.6
             gmodule-export-2.0
             gnome-desktop-3.0