* module/language/tree-il/canonicalize.scm (canonicalize!): Fix a bug in
which the sense of `escape-only?' was reversed. We never saw this
though, because for other reasons, no prompts were being identified as
escape-only.
* module/language/tree-il/peval.scm: Move to its own file. Remove the
bits about <prompt> thunk-application bodies, as they are not
optimizations, simply expectations of the compiler. `canonicalize'
handles that now.
* module/language/tree-il/optimize.scm: Use peval from its module.
Don't call `inline!', as that's useless now.
* module/language/tree-il/canonicalize.scm: New file, implementing a
pass that `compile-tree-il' runs on the result from the optimizer.
The compiler currently expects a <let> form to have bindings, for
example, and this pass turns a <let> without bindings into its body.
* module/language/tree-il/inline.scm: Deprecate, as `peval' does
everything this function ever did.
* module/language/tree-il/compile-glil.scm: Canonicalize after
optimizing. This should allow us to skip the optimizer entirely, if
we want.
* module/Makefile.am: Update and reorder a little bit.
