gentoo-overlay/app-arch/libarchive/files/libarchive-3.2.1-xz-utils-thread-detection.patch

From 7c3148ec0a2fed4834c6f9869ff7d2da77ba804c Mon Sep 17 00:00:00 2001
From: Joerg Sonnenberger <joerg@bec.de>
Date: Wed, 22 Jun 2016 23:03:43 +0200
Subject: [PATCH] Ignore the MT encoder in XZ 5.2 prerelease versions.

---
 configure.ac | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 64775fa..4f7f432 100644
--- a/configure.ac
+++ b/configure.ac
@@ -374,8 +374,11 @@ if test "x$with_lzma" != "xno"; then
   AC_CACHE_CHECK(
     [whether we have multithread support in lzma],
     ac_cv_lzma_has_mt,
-    [AC_COMPILE_IFELSE([
-      AC_LANG_PROGRAM([[#include <lzma.h>]],
+    [AC_LINK_IFELSE([
+      AC_LANG_PROGRAM([[#include <lzma.h>]
+                       [#if LZMA_VERSION < 50020000]
+                       [#error unsupported]
+                       [#endif]],
                       [[lzma_stream_encoder_mt(0, 0);]])],
       [ac_cv_lzma_has_mt=yes], [ac_cv_lzma_has_mt=no])])
   if test "x$ac_cv_lzma_has_mt" != xno; then