* libguile/vm-engine.c (vm_error_wrong_num_args): Sync the registers
before calling scm_wrong_num_args. (The other cases are handled more
uniformly.)
* libguile/vm.c (vm_heapify_frames_1): Add a FIXME: I don't think we
should be modifying the stack.
(scm_vm_save_stack): If stack nulling is enabled, verify the stack here
before reifying it.
* module/language/scheme/spec.scm (scheme): Use primitive-eval here
instead of eval, because at the repl we do want to allow evaluations to
have side effects like setting the current module.
* module/language/scheme/spec.scm (scheme): Specify an evaluator, `eval'.
* module/system/repl/common.scm (repl-default-options): Add option,
`interp', specifying that, if possible, the repl should interpret its
expressions rather than compile them. Defaults to #f.
* module/system/base/syntax.scm (keywords): Don't enable :keywords, it
breaks code that may assume that ':foo is a symbol, like boot-9.
* module/*.scm: Don't use :keywords, use #:keywords. The user can decide
if she wants #:keywords in their .guile, and :keywords might make us
compile modules differently.
