Index: tools/tiffdither.c
===================================================================
--- tools/tiffdither.c.orig	2015-02-18 13:06:47.972867055 +0100
+++ tools/tiffdither.c	2015-02-18 13:12:03.759562692 +0100
@@ -77,6 +77,11 @@
 	outlinesize = TIFFScanlineSize(out);
 	outline = (unsigned char *) _TIFFmalloc(outlinesize);
 
+ 	if (! (inputline && thisline && nextline && outline)) {
+		fprintf(stderr, "Out of memory.\n");
+		return;
+	}
+       
 	/*
 	 * Get first line
 	 */