--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -1,3 +1,11 @@
+2006-03-07  Simon Josefsson  <jas@extundo.com>
+
+	* readline.m4 (gl_FUNC_READLINE): Rewrite the cached part of the
+	test to be side-effect free by storing the result in the cache
+	variable gl_cv_lib_readline, and moving the assignment of
+	LIBREADLINE and LTLIBREADLINE outside the COMMANDS-TO-SET-IT.
+	From Ralf Wildenhues <Ralf.Wildenhues@gmx.de>.
+
 2006-03-07  Simon Josefsson  <jas@extundo.com>
 
 	* gc-random.m4: New file, mostly from gc.m4.  Warn instead of

--- a/m4/readline.m4
+++ b/m4/readline.m4
@@ -1,5 +1,5 @@
-# readline.m4 serial 3
-dnl Copyright (C) 2005 Free Software Foundation, Inc.
+# readline.m4 serial 4
+dnl Copyright (C) 2005, 2006 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -42,23 +42,20 @@
       AC_TRY_LINK([#include <stdio.h>
 #include <readline/readline.h>],
         [readline((char*)0);],
-        gl_cv_lib_readline=yes)
-      if test "$gl_cv_lib_readline" = yes; then
-        if test -n "$extra_lib"; then
-          LIBREADLINE="$LIBREADLINE -l$extra_lib"
-          LTLIBREADLINE="$LTLIBREADLINE -l$extra_lib"
-        fi
-        break
+        [gl_cv_lib_readline=" -l$extra_lib"])
+      if test "$gl_cv_lib_readline" != no; then
+	break
       fi
     done
     LIBS="$am_save_LIBS"
   ])
 
-  if test "$gl_cv_lib_readline" = yes; then
+  if test "$gl_cv_lib_readline" != no; then
     AC_DEFINE(HAVE_READLINE, 1, [Define if you have the readline library.])
-  fi
-
-  if test "$gl_cv_lib_readline" = yes; then
+    if test "$gl_cv_lib_readline" != " -l"; then
+      LIBREADLINE="$LIBREADLINE$gl_cv_lib_readline"
+      LTLIBREADLINE="$LTLIBREADLINE$gl_cv_lib_readline"
+    fi
     AC_MSG_CHECKING([how to link with libreadline])
     AC_MSG_RESULT([$LIBREADLINE])
   else