Remove cond-expand on gauche.sys.threads

Now that we always have thread support, we no longer need those
cond-expands.

configure.ac

@@ -103,9 +103,7 @@ AS_CASE(["$host"],
     GAUCHE_THREAD_TYPE=pthreads
     ],
   [*-*-mingw*], [
-    AS_IF([test $GAUCHE_THREAD_TYPE = "pthreads"],
-          [ AC_MSG_ERROR([pthread can't be used on Windows.  Use --enable-threads=win32 to enable threads]) ],
-          [ GAUCHE_THREAD_TYPE=win32 ])
+    GAUCHE_THREAD_TYPE=win32
     ],
   [
     AC_MSG_ERROR([Can't determine thread subsystem type on $host])

lib/control/pmap.scm

@@ -296,13 +296,9 @@
 
 (define default-mapper
   (make-parameter
-   (cond-expand
-    [gauche.sys.threads
-     (if (= 1 (sys-available-processors))
-       (sequential-mapper)
-       (make-static-mapper))]
-    [else
-     (sequential-mapper)])))
+   (if (= 1 (sys-available-processors))
+     (sequential-mapper)
+     (make-static-mapper))))
 
 ;;;
 ;;; High-level API

libsrc/gauche/process.scm

@@ -71,11 +71,10 @@
           ))
 (select-module gauche.process)
 
-;; Delay-load gauche.charconv
-(autoload gauche.charconv
-          wrap-with-input-conversion wrap-with-output-conversion)
-(autoload gauche.uvector
-          write-uvector)
+;; Delay-load to avoid circular dependency
+(autoload gauche.charconv wrap-with-input-conversion wrap-with-output-conversion)
+(autoload gauche.uvector write-uvector)
+(autoload gauche.threads make-thread thread-start!)
 
 ;; Avoid build dependency issue
 (autoload srfi.19
@@ -429,33 +428,16 @@
   (values iomap toclose ipipes opipes tmpfiles))
 
 ;; Set up source of << and <<< redirection, used inside %setup-iomap.
-;; We don't want to depend on gauche.threads at compile time, so we split
-;; this part to be evaluated at runtime.
-;; Returns updated iomap, toclose, and tmpfiles.
-(without-precompiling
- (define (%setup-<< fd do-file dir arg iomap toclose tmpfiles)
-   (define (write-arg o)
-     (unwind-protect
-         (cond [(eq? dir '<<<) (write arg o)]
-               [(string? arg) (display arg o)]
-               [else (write-uvector arg o)])
-       (close-output-port o)))
-   (cond-expand
-    [gauche.sys.threads
-     (receive (in out) (sys-pipe)
-       (thread-start! (make-thread (cut write-arg out)))
-       (values (acons fd in iomap) (cons in toclose) tmpfiles))]
-    [else
-     ;; If we can't use threads, we fall back to using temporary
-     ;; files.  It has some drawbacks: (1) If we 'exec'-ing
-     ;; (not forking), we don't have chance to remove them, and
-     ;; (2) On Windows we won't be able to remove temp file unless
-     ;; we wait the child process to complete.  We'll do our best
-     ;; anyway.
-     (receive (out nam) (sys-mkstemp (%temp-path-prefix))
-       (write-arg out)
-       (do-file '< fd nam)
-       (values iomap toclose (cons nam tmpfiles)))])))
+(define (%setup-<< fd do-file dir arg iomap toclose tmpfiles)
+  (define (write-arg o)
+    (unwind-protect
+        (cond [(eq? dir '<<<) (write arg o)]
+              [(string? arg) (display arg o)]
+              [else (write-uvector arg o)])
+      (close-output-port o)))
+  (receive (in out) (sys-pipe)
+    (thread-start! (make-thread (cut write-arg out)))
+    (values (acons fd in iomap) (cons in toclose) tmpfiles)))
 
 (define (%ensure-mask mask)
   (cond