Expose unlimited option for HEIF input

src/common.h

@@ -206,6 +206,11 @@ namespace sharp {
   */
   bool ImageTypeSupportsPage(ImageType imageType);
 
+  /*
+    Does this image type support removal of safety limits?
+  */
+  bool ImageTypeSupportsUnlimited(ImageType imageType);
+
   /*
     Open an image from the given InputDescriptor (filesystem, compressed buffer, raw pixel data)
   */