fix hygiene + modules + local macros

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

* module/ice-9/psyntax.scm (syntax-type): Look up the type of the car of
  a form relative to its module, if it is a syntax object. Fixes hygiene
  wrt modules and private macros.

* module/ice-9/syncase.scm (sc-macro): Add a comment.

* module/system/base/pmatch.scm: The big test case: just export pmatch,
  not ppat too.

module/ice-9/psyntax.scm

@@ -972,7 +972,9 @@
        (let ((first (car e)))
          (if (id? first)
              (let* ((n (id-var-name first w))
-                    (b (lookup n r mod))
+                    (b (lookup n r (or (and (syntax-object? first)
+                                            (syntax-object-module first))
+                                       mod)))
                     (type (binding-type b)))
                (case type
                  ((lexical)

module/ice-9/syncase.scm

@@ -42,6 +42,8 @@
     (lambda (exp env)
       (save-module-excursion
        (lambda ()
+         ;; Because memoization happens lazily, env's module isn't
+         ;; necessarily the current module.
          (set-current-module (eval-closure-module (car (last-pair env))))
          (strip-expansion-structures (sc-expand exp)))))))
 

module/system/base/pmatch.scm

@@ -1,6 +1,6 @@
 (define-module (system base pmatch)
   #:use-module (ice-9 syncase)
-  #:export (pmatch ppat))
+  #:export (pmatch))
 ;; FIXME: shouldn't have to export ppat...
 
 ;; Originally written by Oleg Kiselyov. Taken from: