diff --git a/configure.ac b/configure.ac
index 2fbd3a4496..f0f73b4e2f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -569,7 +569,7 @@ AC_EGREP_HEADER([[^A-Za-z0-9_]$1([ 	]+[A-Za-z0-9_]*)?[	 ]*\(],
 		[],
 		[
 		  AC_MSG_NOTICE([adding prototype for $1])
-		  AC_DEFINE(m4_bpatsubst([NEED_PROTO_NAME], [NAME], m4_translit([$1], [[a-z]], [[A-Z]])))
+		  AC_DEFINE([NEED_PROTO_]AS_TR_CPP([$1]))
 		])[]dnl
 ])