prereq check for find -exec +

SVN-Revision: 6940

include/prereq-build.mk

@@ -121,3 +121,11 @@ $(eval $(call Require,gnutar, \
 $(eval $(call RequireCommand,autoconf, \
 	Please install GNU autoconf. \
 ))
+
+define Require/find
+	find . -maxdepth 1 -exec ls {} + > /dev/null 2>&1
+endef
+
+$(eval $(call Require,find, \
+	Please install GNU find 4.2.12 or better. \
+))