lib/cdt/dthdr.h: #include <stdlib.h>
lib/cdt/dthdr.h: #include <stdlib.h>

Instead of declaring externs for the function malloc, realloc and free,
include the stdlib.h header file that includes these declarations.

ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz