diff -Naur pilot-link-0.12.2.orig/m4/threads.m4 pilot-link-0.12.2/m4/threads.m4
--- pilot-link-0.12.2.orig/m4/threads.m4	2005-03-02 23:36:49.000000000 +0100
+++ pilot-link-0.12.2/m4/threads.m4	2007-08-25 20:36:36.000000000 +0200
@@ -5,9 +5,10 @@
 #
 
 AC_DEFUN([PILOT_LINK_THREADS_SUPPORT], [
-	use_threads=false
-	AC_ARG_ENABLE(threads,[  --enable-threads        Add this to have built-in thread safety],use_threads=true)
-	if $use_threads; then
+	use_threads=true
+	AC_ARG_ENABLE([threads], AS_HELP_STRING([--disable-threads], [Build without built-in thread safety (default: test)]))
+
+	if test "x$enable_threads" != "xno"; then
 		ACX_PTHREAD
 		if test x"$acx_pthread_ok" = xno; then
 			use_threads=false