String found where operator expected at ./builder.pl line 207, near "destroy_buildenvironment "swap""
        (Do you need to predeclare destroy_buildenvironment?)
Prototype mismatch: sub main::destroy_buildenvironment () vs none at ./builder.pl line 416.
syntax error at ./builder.pl line 207, near "destroy_buildenvironment "swap""
Execution of ./builder.pl aborted due to compilation errors.