No .DEK file produced even though MDECK compile-time option is specified.
The default SQL(NODECK) compile-time option was in force.
Diagnosing the problem
SQL Preprocessor listing showed the NODECK option was in force.
Resolving the problem
Unlike the Enterprise PL/I for z/OS, the PL/I for AIX SQL Preprocessor has a [NO]DECK compile-time option that defaults to NODECK. Overriding the default by using SQL(DECK) resolves the problem.