Remove TLS configure tests

[Joseph Myers <joseph at codesourcery dot com>]

There seemed to be support in response to
<https://sourceware.org/ml/libc-alpha/2015-10/msg00510.html> for
removing configure tests that exist only to produce errors, where we
expect that tool versions failing the tests would also fail the tests
of minimum GCC / binutils versions.

This patch removes the tests for TLS support as one instance of such
tests.  Since the addition of TLS emulation support in GCC 4.3, I
don't think these tests would have failed even if proper TLS support
(as required by glibc) was missing in that architecture's GCC back
end, so any new glibc ports wanting a substantive test (if there are
actual GCC or binutils versions for those architectures, with
supported version numbers, missing TLS support) would have needed an
architecture-specific test anyway.

Tested for x86_64 and x86 (testsuite, and that installed shared
libraries are unchanged by the patch).

2015-10-26  Joseph Myers  <joseph@codesourcery.com>

	* configure.ac (libc_cv_gcc___thread): Remove configure test.
	(libc_cv_gcc_tls_model_attr): Likewise.
	* configure: Regenerated.

diff --git a/configure b/configure
index 22aa1b9..ac09f40 100755
--- a/configure
+++ b/configure
@@ -6170,58 +6170,6 @@ if test "$libc_cv_gcc_builtin_redirection" = no; then
   as_fn_error $? "support for the symbol redirection needed" "$LINENO" 5
 fi
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for __thread" >&5
-$as_echo_n "checking for __thread... " >&6; }
-if ${libc_cv_gcc___thread+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat > conftest.c <<\EOF
-__thread int a = 42;
-EOF
-if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c >&5'
-  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }; then
-  libc_cv_gcc___thread=yes
-else
-  libc_cv_gcc___thread=no
-fi
-rm -f conftest*
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_gcc___thread" >&5
-$as_echo "$libc_cv_gcc___thread" >&6; }
-if test "$libc_cv_gcc___thread" = no; then
-  as_fn_error $? "support for the __thread keyword is required" "$LINENO" 5
-fi
-
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for tls_model attribute" >&5
-$as_echo_n "checking for tls_model attribute... " >&6; }
-if ${libc_cv_gcc_tls_model_attr+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat > conftest.c <<\EOF
-extern __thread int a __attribute__((tls_model ("initial-exec")));
-EOF
-if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -S -Werror conftest.c >&5'
-  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }; then
-  libc_cv_gcc_tls_model_attr=yes
-else
-  libc_cv_gcc_tls_model_attr=no
-fi
-rm -f conftest*
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_gcc_tls_model_attr" >&5
-$as_echo "$libc_cv_gcc_tls_model_attr" >&6; }
-if test "$libc_cv_gcc_tls_model_attr" = no; then
-  as_fn_error $? "support for the tls_model attribute is required" "$LINENO" 5
-fi
-
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for compiler option to disable generation of FMA instructions" >&5
 $as_echo_n "checking for compiler option to disable generation of FMA instructions... " >&6; }
 if ${libc_cv_cc_nofma+:} false; then :
diff --git a/configure.ac b/configure.ac
index 6947555..4d6852e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1581,36 +1581,6 @@ if test "$libc_cv_gcc_builtin_redirection" = no; then
   AC_MSG_ERROR([support for the symbol redirection needed])
 fi
 
-dnl Check whether the compiler supports the __thread keyword.
-AC_CACHE_CHECK([for __thread], libc_cv_gcc___thread,
-[cat > conftest.c <<\EOF
-__thread int a = 42;
-EOF
-if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c >&AS_MESSAGE_LOG_FD]); then
-  libc_cv_gcc___thread=yes
-else
-  libc_cv_gcc___thread=no
-fi
-rm -f conftest*])
-if test "$libc_cv_gcc___thread" = no; then
-  AC_MSG_ERROR([support for the __thread keyword is required])
-fi
-
-dnl Check whether the compiler supports the tls_model attribute.
-AC_CACHE_CHECK([for tls_model attribute], libc_cv_gcc_tls_model_attr, [dnl
-cat > conftest.c <<\EOF
-extern __thread int a __attribute__((tls_model ("initial-exec")));
-EOF
-if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -S -Werror conftest.c >&AS_MESSAGE_LOG_FD]); then
-  libc_cv_gcc_tls_model_attr=yes
-else
-  libc_cv_gcc_tls_model_attr=no
-fi
-rm -f conftest*])
-if test "$libc_cv_gcc_tls_model_attr" = no; then
-  AC_MSG_ERROR([support for the tls_model attribute is required])
-fi
-
 dnl Determine how to disable generation of FMA instructions.
 AC_CACHE_CHECK([for compiler option to disable generation of FMA instructions],
 	       libc_cv_cc_nofma, [dnl

-- 
Joseph S. Myers
joseph@codesourcery.com