instead of allowing no #%module-begin, catch it and report a suitable error
instead of allowing no #%module-begin, catch it and report a suitable error

svn: r17191

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket