primitive-load-path so that backtraces get narrowed properly at
the top.
* boot-9.scm (top-repl): Save stack already in signal handler in
order to narrow it correctly.
(save-stack): Adjust narrowing tag for the top of load-stacks.
basic-load. This is probably wrong, but hopefully the entire
source access system will be revised soon anyway, and this will
make require behave more like Emacs Lisp's require. If this
breaks something, please let me know. Maybe this is real dumb.
* r4rs.scm: update primitive-load usage.
Don't define read-sharp.
* boot-9.scm: use read-hash-extend to install extra read syntax.
(read-sharp): removed.
Adjust usage of primitive-load-path, read, which no longer take
case_i or read-sharp arguments.
(macroexpand-1, macroexpand): Use local-ref instead of defined?
and eval.
* r4rs.scm (%load-verbosely): Use "module-defined?" instead of
"defined?".
* slib.scm (defined?): New function to take the place of the
builtin "defined?". It allways examines the slib module.
