Add configure_for_canaries helper script.

.gitattributes

@@ -5,6 +5,7 @@ canaries/canaries_callbacks.c -text
 canaries/debug_canary_callbacks.c -text
 /configure -text
 /configure.in -text
+/configure_for_canaries -text
 /configure_for_cgc -text
 /configure_for_cinderella -text
 /configure_for_rss -text

configure_for_canaries

+#!/bin/bash
+
+./configure --enable-libc --enable-canaries $*