x86: Default CET run-time support to auto

CET has been added since GCC 8.  This patch defaults CET run-time support
to auto.  It enables CET run-time support if asssembler supports CET
instructions and multi-byte NOPs are enabled via SSE2.

config/

	* cet.m4 (GCC_CET_FLAGS): Change default to auto.

gcc/

	* configure: Regenerated.

libatomic/

	* configure: Regenerated.

libbacktrace/

	* configure: Regenerated.

libcc1/

	* configure: Regenerated.

libcpp/

	* configure: Regenerated.

libdecnumber/

	* configure: Regenerated.

libgcc/

	* configure: Regenerated.

libgfortran/

	* configure: Regenerated.

libgomp/

	* configure: Regenerated.

libitm/

	* configure: Regenerated.

libobjc/

	* configure: Regenerated.

libquadmath/

	* configure: Regenerated.

libsanitizer/

	* configure: Regenerated.

libssp/

	* configure: Regenerated.

libstdc++-v3/

	* configure: Regenerated.

libvtv/

	* configure: Regenerated.

zlib/

	* configure: Regenerated.

libssp/ChangeLog

@@ -1,3 +1,7 @@
+2020-05-14  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* configure: Regenerated.
+
 2020-02-12  Sandra Loosemore  <sandra@codesourcery.com>
 
 	PR libstdc++/79193

libssp/configure

@@ -1419,7 +1419,7 @@ Optional Features:
                           do not reject slow dependency extractors
   --disable-dependency-tracking
                           speeds up one-time build
-  --enable-cet            enable Intel CET in target libraries [default=no]
+  --enable-cet            enable Intel CET in target libraries [default=auto]
   --disable-symvers       disable symbol versioning for libssp
   --enable-shared[=PKGS]  build shared libraries [default=yes]
   --enable-static[=PKGS]  build static libraries [default=yes]
@@ -4325,7 +4325,7 @@ if test "${enable_cet+set}" = set; then :
                           esac
 
 else
-  enable_cet=no
+  enable_cet=auto
 fi