The complete structure definition has to be listed inside the declare
section of the structure variable for ecpg to be able to understand it.

The error message for "no data" in an exec sql insert select from statement
has to be 100.

sqlwarn[6] should be 'W' if the PRECISION or SCALE value specified in a SET
DESCRIPTOR statement will be ignored.

If a NOTICE message is given by the backend it should not be printed to
stderr. Instead it should be listed as a warning.

The error handling has to be improved by adding additional error-rules to
the parser.

it would be nice to be able to use :var[:index] or :var[<integer>] as
cvariable for an array var

How can one insert arrays from c variables?

support for dynamic SQL with unknown number of variables with DESCRIPTORS

What happens to the output variable during read if there was an
indicator-error? 

Add a semantic check level, e.g. check if a table really exists.

Missing statements:
 - exec sql ifdef
 - exec sql allocate
 - exec sql deallocate
 - SQLSTATE
