Ignore explicit phase specification for imports in `library' form.

* module/ice-9/r6rs-libraries.scm (library): Unwrap the `for' sub-form
  during export resolution the same way that `import' does.
* test-suite/tests/rnrs-libraries.test ("implicit phasing"): New test
  prefix and tests.

module/ice-9/r6rs-libraries.scm

@@ -161,7 +161,13 @@
        (and-map identifier? #'(name name* ...))
        (call-with-values
            (lambda ()
-             (compute-exports (map resolve-r6rs-interface #'(ispec ...))
+             (compute-exports 
+              (map (lambda (im)
+                     (syntax-case im (for)
+                       ((for import-set import-level ...)
+                        (resolve-r6rs-interface #'import-set))
+                       (import-set (resolve-r6rs-interface #'import-set))))
+                   #'(ispec ...))
               #'(espec ...)))
          (lambda (exports re-exports)
            (with-syntax (((e ...) exports)

test-suite/tests/rnrs-libraries.test

@@ -114,6 +114,21 @@
     (equal? (eval '(double 20) (current-module))
             40)))
 
+;; Guile should ignore explicit phase specifications
+;;
+(with-test-prefix "implicit phasing"
+  (with-test-prefix "in library form"
+    (pass-if "explicit phasing ignored"
+      (import (for (guile) (meta -1))) #t))
+
+  (with-test-prefix "in library form"
+    (pass-if "explicit phasing ignored"
+      (save-module-excursion
+       (lambda () 
+         (library (test) 
+           (export) 
+           (import (for (guile) (meta -1)))) 
+         #t)))))
 
 ;; Now import features.
 ;;