diff --git a/m4/plugin.m4 b/m4/plugin.m4
index 94b6a459..da0569c3 100644
--- a/m4/plugin.m4
+++ b/m4/plugin.m4
@@ -1,8 +1,8 @@
 # From https://github.com/collectd/collectd/blob/master/configure.ac
 # Dependency handling currently unused
 
-m4_define([toupper], [translit([$1], [a-z], [A-Z])])
-m4_define([sanitize], [translit([$1], [-], [_])])
+define([toupper], [translit([$1], [a-z], [A-Z])])
+define([sanitize], [translit([$1], [-], [_])])
 
 # AC_PLUGIN(name, default, info)
 # ------------------------------------------------------------
@@ -31,4 +31,4 @@ Optional Plugins:])
        	    AC_DEFINE([HAVE_]PLUGGY[_PLUGIN], 1, [Define to 1 if the $1 plugin is enabled.])
     fi
     AM_CONDITIONAL([BUILD_]PLUGGY[_PLUGIN], test "x$enable_plugin" = "xyes")
-    enable_pluggy="$enable_plugin"])# AC_ARG_ENABLE
+    enable_pluggy="$enable_plugin"])