Windows distribution: remove compiler-specific libraries

Building creates compiler-specific files in "lib/msvc"
or "lib/gcc". For consistency, strip those directories
when creating a distribution.

The newly added ".def" file provides information that
would otherwise be lost by removing the MSVC ".lib"
file from the distribution.

Removing the compiler-specific ".obj" files means that
used to be included for linking extensions. My guess
is that the files are now completely unused.

Makefile

@@ -492,6 +492,7 @@ bundle-from-server:
 	$(BUNDLE_RACO) pkg install $(REMOTE_INST_AUTO) $(PKG_SOURCE_MODE) $(REQUIRED_PKGS)
 	$(BUNDLE_RACO) pkg install $(REMOTE_INST_AUTO) $(PKG_SOURCE_MODE) $(PKGS)
 	$(RACKET) -l setup/unixstyle-install post-adjust "$(SOURCE_MODE)" "$(PKG_SOURCE_MODE)" racket bundle/racket
+	$(RACKET) -l setup/winstrip bundle/racket
 	$(RACKET) -l setup/winvers-change bundle/racket
 
 UPLOAD_q = --readme "$(README)" --upload "$(UPLOAD)" --desc "$(DIST_DESC)"

racket/collects/setup/winstrip.rkt

@@ -1,5 +1,7 @@
 #lang racket/base
-(require racket/cmdline)
+(require racket/cmdline
+         setup/cross-system
+         racket/file)
 
 (module test racket/base)
 
@@ -20,6 +22,7 @@
   (printf "Deleting ~a\n" p)
   (delete-file p))
 
+(when (eq? 'windows (cross-system-type))
   (for ([a (directory-list dir)])
     (define f (build-path dir a))
     (define b (path-element->bytes a))
@@ -39,4 +42,14 @@
                           (not (regexp-match? #rx#"3m" b))))))
       (delete-file* f)))
   
+  ;; Delete any subdirectory that contains ".lib" files.
+  ;; Those are compiler-specific directories, and so we
+  ;; don't want to include them in a distribution.
+  (for ([f (in-directory (build-path dir "lib"))])
+    (when (and (directory-exists? f)
+               (for/or ([f (in-directory f)])
+                 (regexp-match? #rx"[.]lib$" f)))
+      (delete-directory/files f))))
+
+