Return value of enlarge_query_statement() is never evaluated

Hello,

while fixing the ResolveOneParam() bug, I saw that the return value of
enlarge_query_statement() is ignored by all calling functions.

Since that function might free the allocated memory, the result might be
disastrous (i.e. crashing the application). This function is only called via
macros, so I don't see an easy way to fix this.

Hiroshi, what do you think?

Rainer