configure.ac: Don't link weston to cairo or image libraries
We were pulling in cairo and the image loading libraries through libshared.
Split out libshared into a core libshared and a libshared-cairo that
pulls in the extra libraries.
diff --git a/shared/cairo-util.h b/shared/cairo-util.h
index 3a760a4..64ed03f 100644
--- a/shared/cairo-util.h
+++ b/shared/cairo-util.h
@@ -23,6 +23,8 @@
#ifndef _CAIRO_UTIL_H
#define _CAIRO_UTIL_H
+#include <pixman.h>
+
void
surface_flush_device(cairo_surface_t *surface);
@@ -87,4 +89,7 @@
enum theme_location
theme_get_location(struct theme *t, int x, int y, int width, int height, int flags);
+pixman_image_t *
+load_image(const char *filename);
+
#endif