* module/language/cps/compile-bytecode.scm (compile-bytecode):
* module/language/tree-il/compile-bytecode.scm (compile-bytecode):
* module/language/tree-il/compile-cps.scm (compile-cps): Rely on
compiler to lower incoming term already.
* module/language/tree-il/optimize.scm (make-lowerer): New procedure.
* module/system/base/compile.scm (compute-lowerer): New procedure,
replaceing add-default-optimizations.
(compute-compiler): Lower before running compiler.
* module/system/base/language.scm (<language>): Change
optimizations-for-level field to "lowerer".
* module/scripts/compile.scm (%options, compile): Parse -O0, -O1 and so
on to #:optimization-level instead of expanding to all the
optimization flags.
* module/language/cps/optimize.scm (lower-cps): Move here from
compile-bytecode.scm.
(make-cps-lowerer): New function.
* module/language/cps/spec.scm (cps): Declare lowerer.
* module/language/tree-il/compile-cps.scm: New module implementing CPS
conversion of Tree-IL.
* module/Makefile.am:
* module/language/tree-il/spec.scm:
* module/language/cps/spec.scm: Integrate CPS in the build and language
system.
