Use a non-empty test program to test ability to link.

On bare-metal targets, I/O support is typically provided by a BSP and
requires a linker script and/or hosting library to be specified on the
linker command line.  Linking an empty program with the default linker
script may succeed, however, which confuses libstdc++ configuration
when programs that probe for the presence of various I/O features fail
with link errors.

2020-02-12  Sandra Loosemore  <sandra@codesourcery.com>

	PR libstdc++/79193
	PR libstdc++/88999

	config/
	* no-executables.m4: Use a non-empty program to test for linker
	support.

	libgcc/
	* configure: Regenerated.

	libgfortran/
	* configure: Regenerated.

	libiberty/
	* configure: Regenerated.

	libitm/
	* configure: Regenerated.

	libobjc/
	* configure: Regenerated.

	libquadmath/
	* configure: Regenerated.

	libssp/
	* configure: Regenerated.

	libstdc++v-3/
	* configure: Regenerated.

1 files changed, 2 insertions, 2 deletions

diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index a39c33b055d..9f9c5a2419a 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -4130,11 +4130,11 @@ done
 
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-
+#include <stdio.h>
 int
 main ()
 {
-
+printf ("hello world\n");
   ;
   return 0;
 }