* src/LR0.c (new_state, get_state): Complete TRACE code.

* src/LR0.c (new_state, get_state): Complete TRACE code.
* src/closure.c: Include `reader.h' to get `tags', needed by the
trace code.
Rename the conditional DEBUG as TRACE.
Output consistently TRACEs to stderr, not stdout.
* src/derives.c: Likewise.
* src/reduce.c: (inaccessable_symbols): Using if is better style
than goto.
Use `#if TRACE' instead of `#if 0' for tracing code.