From: Roland McGrath <roland@redhat.com>
Date: Fri, 23 Jan 2009 22:27:39 +0000 (-0800)
Subject: Make the __thread check more precisely representative to catch bad tools with nonwork... 
X-Git-Tag: elfutils-0.140~25^2~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e72bf15cdf135a742a9214535a86fb5b2d420180;p=thirdparty%2Felfutils.git

Make the __thread check more precisely representative to catch bad tools with nonworking partial support.
---

diff --git a/configure.ac b/configure.ac
index 24353f63d..d7d58e1a1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -75,12 +75,19 @@ AS_IF([test "x$ac_cv_c99" != xyes],
       AC_MSG_ERROR([gcc with C99 support required]))
 
 AC_CACHE_CHECK([for __thread support], ac_cv_tls, [dnl
+# Use the same flags that we use for our DSOs, so the test is representative.
+# Some old compiler/linker/libc combinations fail some ways and not others.
+save_CFLAGS="$CFLAGS"
+save_LDFLAGS="$LDFLAGS"
+CFLAGS="-fpic $CFLAGS"
+LDFLAGS="-shared -Wl,-z,defs,-z,relro $LDFLAGS"
 AC_LINK_IFELSE([dnl
 AC_LANG_PROGRAM([[#undef __thread
-static __thread int a __attribute__ ((tls_model ("local-dynamic")));
-int foo (int b) { return a + b; }]],
+static __thread int a; int foo (int b) { return a + b; }]],
 		[[exit (foo (0));]])],
-	       ac_cv_tls=yes, ac_cv_tls=no)])
+	       ac_cv_tls=yes, ac_cv_tls=no)
+CFLAGS="$save_CFLAGS"
+LDFLAGS="$save_LDFLAGS"])
 AS_IF([test "x$ac_cv_tls" != xyes],
       AC_MSG_ERROR([__thread support required]))