Try to fix linking

We need to link against gdk against pangoft2 on X11.
Also add Requires.private to gdk-3.0.pc, and try to clean
things up some.

https://bugzilla.gnome.org/show_bug.cgi?id=665326

configure.ac

@@ -1257,20 +1257,24 @@ fi
 CFLAGS="$saved_cflags"
 LDFLAGS="$saved_ldflags"
 
-GDK_PACKAGES="$PANGO_PACKAGES $GIO_PACKAGE $X_PACKAGES $WAYLAND_PACKAGES gdk-pixbuf-2.0 $cairo_backends cairo-gobject"
+GDK_PACKAGES="$PANGO_PACKAGES gdk-pixbuf-2.0 cairo cairo-gobject"
+GDK_PRIVATE_PACKAGES="$GIO_PACKAGE $X_PACKAGES $WAYLAND_PACKAGES $cairo_backends"
+if test "x$enable_x11_backend" = xyes; then
+  GDK_PRIVATE_PACKAGES="$GDK_PRIVATE_PACKAGES pangoft2"
+fi
 
-GDK_DEP_LIBS="$GDK_EXTRA_LIBS `$PKG_CONFIG --libs $GDK_PACKAGES` $MATH_LIB"
-GDK_DEP_CFLAGS="`$PKG_CONFIG --cflags  gthread-2.0 $GDK_PACKAGES` $GDK_EXTRA_CFLAGS"
+GDK_DEP_LIBS="$GDK_EXTRA_LIBS `$PKG_CONFIG --libs $GDK_PACKAGES $GDK_PRIVATE_PACKAGES` $MATH_LIB"
+GDK_DEP_CFLAGS="`$PKG_CONFIG --cflags  gthread-2.0 $GDK_PACKAGES $GDK_PRIVATE_PACKAGES` $GDK_EXTRA_CFLAGS"
 #
 # If we aren't writing explicit dependencies, then don't put the extra libraries we need
 # into the pkg-config files
 #
 if test $enable_explicit_deps != yes ; then
-  GDK_PACKAGES="$PANGO_PACKAGES gdk-pixbuf-2.0 cairo-gobject"
   GDK_EXTRA_LIBS=
 fi
 
 AC_SUBST(GDK_PACKAGES)
+AC_SUBST(GDK_PRIVATE_PACKAGES)
 AC_SUBST(GDK_EXTRA_LIBS)
 AC_SUBST(GDK_EXTRA_CFLAGS)
 AC_SUBST(GDK_DEP_LIBS)
@@ -1314,8 +1318,8 @@ fi
 GTK_EXTRA_LIBS=
 
 GTK_EXTRA_CFLAGS=
-GTK_DEP_LIBS="$GDK_EXTRA_LIBS $GTK_DEP_LIBS_FOR_X `$PKG_CONFIG --libs $PANGO_PACKAGES $GTK_PACKAGES_FOR_X $GTK_PACKAGES` $GTK_EXTRA_LIBS $MATH_LIB"
-GTK_DEP_CFLAGS="`$PKG_CONFIG --cflags  gthread-2.0 $GDK_PACKAGES $GTK_PACKAGES` $GDK_EXTRA_CFLAGS $GTK_EXTRA_CFLAGS"
+GTK_DEP_LIBS="$GDK_EXTRA_LIBS $GTK_DEP_LIBS_FOR_X `$PKG_CONFIG --libs $PANGO_PACKAGES $GTK_PACKAGES_FOR_X $GTK_PACKAGES $GTK_PRIVATE_PACKAGES` $GTK_EXTRA_LIBS $MATH_LIB"
+GTK_DEP_CFLAGS="`$PKG_CONFIG --cflags  gthread-2.0 $GDK_PACKAGES $GTK_PACKAGES $GTK_PRIVATE_PACKAGES` $GDK_EXTRA_CFLAGS $GTK_EXTRA_CFLAGS"
 
 if test x"$os_win32" = xyes; then
   GTK_EXTRA_CFLAGS="$msnative_struct"

gdk-3.0.pc.in

@@ -8,5 +8,6 @@ Name: GDK
 Description: GTK+ Drawing Kit
 Version: @VERSION@
 Requires: @GDK_PACKAGES@
+Requires.private: @GDK_PRIVATE_PACKAGES@
 Libs: -L${libdir} -lgdk-3 @GDK_EXTRA_LIBS@
 Cflags: -I${includedir}/gtk-@GTK_API_VERSION@ @GDK_EXTRA_CFLAGS@