[gold] PATCH: Check if -fpic -mtls-dialect=gnu2 works

["H.J. Lu" <hongjiu dot lu at intel dot com>]

Hi Ian,

"-fpic -mtls-dialect=gnu2" isn't working for x32 yet.  This patch checks
if -fpic -mtls-dialect=gnu2 works before enabling it.  OK to install?

Thanks.


H.J.
---
2012-01-30  H.J. Lu  <hongjiu.lu@intel.com>
 
	* configure.ac: Check if -fpic -mtls-dialect=gnu2 works.
	* configure: Regenerated.
 
diff --git a/gold/configure b/gold/configure
index aca7cab..b1744a8 100755
--- a/gold/configure
+++ b/gold/configure
@@ -6437,10 +6437,16 @@ fi
 
 
 save_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -mtls-dialect=gnu2"
+CFLAGS="$CFLAGS -fpic -mtls-dialect=gnu2"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-int i;
+
+__thread int i;
+void foo (void)
+{
+  i = 10;
+}
+
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
   have_tls_gnu2=yes
diff --git a/gold/configure.ac b/gold/configure.ac
index e49bf21..edc5917 100644
--- a/gold/configure.ac
+++ b/gold/configure.ac
@@ -359,8 +359,14 @@ AM_CONDITIONAL(OMP_SUPPORT, test "$gold_cv_c_threadprivate" = "yes")
 
 dnl Test for the -ftls-dialect=gnu2 option.
 save_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -mtls-dialect=gnu2"
-AC_COMPILE_IFELSE([int i;], [have_tls_gnu2=yes], [have_tls_gnu2=no])
+CFLAGS="$CFLAGS -fpic -mtls-dialect=gnu2"
+AC_COMPILE_IFELSE([
+__thread int i;
+void foo (void)
+{
+  i = 10;
+}
+], [have_tls_gnu2=yes], [have_tls_gnu2=no])
 CFLAGS="$save_CFLAGS"
 AM_CONDITIONAL(TLS_GNU2_DIALECT, test "$have_tls_gnu2" = "yes")