configure.ac: add option --enable-thread-tls to manage thread ssl support

Add option --enable-thread-tls to manage the including of thread
local storage, so we could explicitly disable it.

Upstream-Status: Pending

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
 configure.ac | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/configure.ac b/configure.ac
index 474e094..cedca54 100644
--- a/configure.ac
+++ b/configure.ac
@@ -120,6 +120,9 @@ AC_ARG_ENABLE(memtrace,
 AC_ARG_ENABLE(ssl,
               [  --enable-ssl        Enable SSL support.],,enable_ssl="auto")
 
+AC_ARG_ENABLE(thread-tls,
+              [  --enable-thread-tls        Enable Thread Transport Layer Security support.],,enable_thread_tls="no")
+
 AC_ARG_ENABLE(dynamic-linking,
               [  --enable-dynamic-linking        Link everything dynamically.],,enable_dynamic_linking="auto")
 
@@ -381,12 +384,14 @@ dnl ***************************************************************************
 dnl Is the __thread keyword available?
 dnl ***************************************************************************
 
-AC_LINK_IFELSE([AC_LANG_PROGRAM(
-[[#include <pthread.h>
-__thread int a;
-]],
-[a=0;])],
-[ac_cv_have_tls=yes; AC_DEFINE_UNQUOTED(HAVE_THREAD_KEYWORD, 1, "Whether Transport Layer Security is supported by the system")])
+if test "x$enable_thread_tls" != "xno"; then
+    AC_LINK_IFELSE([AC_LANG_PROGRAM(
+    [[#include <pthread.h>
+    __thread int a;
+    ]],
+    [a=0;])],
+    [ac_cv_have_tls=yes; AC_DEFINE_UNQUOTED(HAVE_THREAD_KEYWORD, 1, "Whether Transport Layer Security is supported by the system")])
+fi
 
 dnl ***************************************************************************
 dnl How to do static linking?
-- 
1.9.1