[cc65] Regression in type composition

[acqn]

1de1855 is correct when

void foo(int (*)(int));
void foo(int (*)(long)); /* Error: Conflicting function types for 'foo' */

but

void foo();              /* OK */
void foo(int (*)(int));  /* OK */
void foo(int (*)(long)); /* WRONG: Should be an error */

The cause of the issue is easy to find out and a quick fix is done already.