Die on missing host fragments, let missing target fragments pass.

binutils/configure.in

@@ -0,0 +1,20 @@
+# This file is a shell script that supplies the information necessary
+# to tailor a template configure script into the configure script
+# appropriate for this directory.  For more information, check any
+# existing configure script.
+
+srctrigger=ar.c
+srcname="binutils"
+
+# per-host:
+
+if [ ! -f config/hmake-${host} ] ; then
+	echo No such host available: ${host}
+	exit 1
+fi
+
+# per-target:
+
+files=
+links=
+