allocate free variables inline to closures

allocate free variables inline to closures

* libguile/_scm.h (SCM_OBJCODE_MINOR_VERSION): Bump.

* libguile/programs.h (SCM_PROGRAM_FREE_VARIABLES)
  (SCM_PROGRAM_FREE_VARIABLE_REF, SCM_PROGRAM_FREE_VARIABLE_SET)
  (SCM_PROGRAM_NUM_FREE_VARIABLES):
* libguile/programs.c (scm_make_program, scm_program_num_free_variables)
  (scm_program_free_variable_ref, scm_program_free_variable_set_x):
  Allocate free variables inline with programs, instead of being in a
  vect. Should improve locality, and require fewer local variables in
  the VM.

* libguile/vm-engine.c (vm_engine): Remove free_vars and free_vars_count
  variables.

* libguile/vm-engine.h (CACHE_PROGRAM): No need to muck with free_vars
  and free_vars_count.
  (CHECK_FREE_VARIABLE): Update for inline free vars.

* libguile/vm-i-system.c (FREE_VARIABLE_REF): Update for inline free
  vars.
  (make-closure, fix-closure): Take the closure vals as separate stack
  args, and copy or fix them inline into the appropriate closure.

* module/language/objcode/spec.scm (program-free-variables): Define a
  local version of this removed function.

* module/language/tree-il/compile-glil.scm (flatten): Adjust to not make
  a vector when making closures.

* module/system/vm/program.scm: Export program-num-free-variables,
  program-free-variable-ref, program-free-variable-set!, and remove
  program-free-variables.

* test-suite/tests/tree-il.test ("lambda"): Update to not make vectors
  when making closures.