Index: threads.c
===================================================================
RCS file: /cvsroot/guile/guile/guile-core/libguile/threads.c,v
retrieving revision 1.84.2.5
retrieving revision 1.84.2.6
diff -u -r1.84.2.5 -r1.84.2.6
--- threads.c	25 Jul 2006 00:09:30 -0000	1.84.2.5
+++ threads.c	13 Dec 2006 23:55:51 -0000	1.84.2.6
@@ -141,9 +141,32 @@
 static int
 thread_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
 {
+  /* On a Gnu system pthread_t is an unsigned long, but on mingw it's a
+     struct.  A cast like "(unsigned long) t->pthread" is a syntax error in
+     the struct case, hence we go via a union, and extract according to the
+     size of pthread_t.  */
+  union {
+    pthread_t p;
+    unsigned short us;
+    unsigned int   ui;
+    unsigned long  ul;
+    scm_t_uintmax  um;
+  } u;
   scm_i_thread *t = SCM_I_THREAD_DATA (exp);
+  scm_i_pthread_t p = t->pthread;
+  scm_t_uintmax id;
+  u.p = p;
+  if (sizeof (p) == sizeof (unsigned short))
+    id = u.us;
+  else if (sizeof (p) == sizeof (unsigned int))
+    id = u.ui;
+  else if (sizeof (p) == sizeof (unsigned long))
+    id = u.ul;
+  else
+    id = u.um;
+
   scm_puts ("#<thread ", port);
-  scm_uintprint ((size_t)t->pthread, 10, port);
+  scm_uintprint (id, 10, port);
   scm_puts (" (", port);
   scm_uintprint ((scm_t_bits)t, 16, port);
   scm_puts (")>", port);