Make avx2 configure test work with -O2

When configured with --extra-cflags=-O2 gcc optimised out the test
and the readelf failed the check leaving avx2 disabled.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1465557378-24105-2-git-send-email-dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/configure b/configure
index cbe013b6bd..3c0e279762 100755
--- a/configure
+++ b/configure
@@ -1781,7 +1781,7 @@ fi
 cat > $TMPC << EOF
 static void bar(void) {}
 static void *bar_ifunc(void) {return (void*) bar;}
-static void foo(void) __attribute__((ifunc("bar_ifunc")));
+void foo(void) __attribute__((ifunc("bar_ifunc")));
 int main(void) { foo(); return 0; }
 EOF
 if compile_prog "-mavx2" "" ; then