#11 (1.6.0) Reopening bug #986842

I'm reopening bug #986842. The error still exists in
version 1.6.0. From the original bug report by Rodolfo
Azevedo:

"Delayed assignments in ac_regs with formats
When you declare an ac_reg with a format and compile
the model with -dy (delayed assignments), there will be
a compile error:
commit_delays function undeclared."