diff --git a/mi/mibitblt.c b/mi/mibitblt.c
index 57d46ee38..452727455 100644
--- a/mi/mibitblt.c
+++ b/mi/mibitblt.c
@@ -61,19 +61,8 @@ SOFTWARE.
 #include "Xmd.h"
 #include "servermd.h"
 
-#ifdef WIN32
-static 
-int ffs(int word) {
-     int i;
-     if (!word)
-         return 0;
-     i = 0;
-     for (;;)
-     {
-         if (((1 << i++) & word) != 0)
-             return i;
-     }
-}
+#ifndef HAS_FFS
+extern int ffs(int);
 #endif
 
 /* MICOPYAREA -- public entry for the CopyArea request