make sure we compile boot code in (guile), not (guile-user)

make sure we compile boot code in (guile), not (guile-user)

* libguile/eval.h:
* libguile/eval.c (scm_m_eval_when): Define a cheap eval-when, used
  before syncase has booted.

* module/Makefile.am: Reorder to put (system vm) and (system repl)
  modules after the compiler, as they are not needed at runtime.

* module/ice-9/boot-9.scm: Move the eval-when earlier, to be the first
  thing -- so when we recompile Guile we do so all in the '(guile)
  module, not '(guile-user).

* module/ice-9/compile-psyntax.scm: Rewrite to assume that psyntax.scm
  will eval-when to set its module, etc. Have everything in a let --
  otherwise the `format' call is in (guile), but `target' was defined
  in (guile-user). Also, write in an eval-when to the expanded file.

* module/ice-9/psyntax-pp.scm: Regenerate.

* module/ice-9/networking.scm:
* module/ice-9/psyntax.scm:
* module/ice-9/r4rs.scm: Sprinkles of eval-when, for flavor.