--- a/configure.ac~	2016-06-28 13:37:56.000000000 +0300
+++ b/configure.ac	2016-06-28 13:45:11.187000000 +0300
@@ -377,7 +377,7 @@ if test "x$with_lzma" != "xno"; then
       AC_LANG_PROGRAM([[#include <lzma.h>]],
                       [[lzma_stream_encoder_mt(0, 0);]])],
       [ac_cv_lzma_has_mt=yes], [ac_cv_lzma_has_mt=no])])
-  if test "x$ac_cv_lzma_has_mt" != xno; then
+  if test "x$ac_cv_lzma_has_mt" == xunknown; then
 	  AC_DEFINE([HAVE_LZMA_STREAM_ENCODER_MT], [1], [Define to 1 if you have the `lzma_stream_encoder_mt' function.])
   fi
 fi