diff --git a/legacy/embryo/m4/ac_attribute.m4 b/legacy/embryo/m4/ac_attribute.m4
index e0df55d985..3926d23d56 100644
--- a/legacy/embryo/m4/ac_attribute.m4
+++ b/legacy/embryo/m4/ac_attribute.m4
@@ -1,7 +1,9 @@
+dnl Copyright (C) 2004-2008 Kim Woelders
 dnl Copyright (C) 2008 Vincent Torri <vtorri at univ-evry dot fr>
 dnl That code is public domain and can be freely used or copied.
+dnl Originally snatched from somewhere...
 
-dnl Macro that check if the compiler supports __atribute__
+dnl Macro for checking if the compiler supports __attribute__
 
 dnl Usage: AC_C___ATTRIBUTE__
 dnl call AC_DEFINE for HAVE___ATTRIBUTE__ and __UNUSED__
@@ -19,14 +21,14 @@ AC_CACHE_VAL([ac_cv___attribute__],
    [AC_TRY_COMPILE(
        [
 #include <stdlib.h>
-       ],
-       [
+
 int func(int x);
 int foo(int x __attribute__ ((unused)))
 {
    exit(1);
 }
        ],
+       [],
        [ac_cv___attribute__="yes"],
        [ac_cv___attribute__="no"]
     )]
@@ -36,9 +38,9 @@ AC_MSG_RESULT($ac_cv___attribute__)
 
 if test "x${ac_cv___attribute__}" = "xyes" ; then
    AC_DEFINE([HAVE___ATTRIBUTE__], [1], [Define to 1 if your compiler has __attribute__])
-   AC_DEFINE([__UNUSED__], [__attribute__((unused))], [Define to __attribute__((unused)) if your compiler has __attribute__])
+   AC_DEFINE([__UNUSED__], [__attribute__((unused))], [Macro declaring a function argument to be unused])
   else
-    AC_DEFINE([__UNUSED__], [], [Define to nothing if your compiler does not support __attribute__])
+    AC_DEFINE([__UNUSED__], [], [Macro declaring a function argument to be unused])
 fi
 
 ])