diff --git a/configure.in b/configure.in
index 82db8b3e..b464c7b9 100644
--- a/configure.in
+++ b/configure.in
@@ -39,7 +39,7 @@ if test "$ac_cv_check_symbol_$1" = yes; then
 changequote(,)dnl
   ac_tr_symbol=`echo $1 | tr '[a-z]' '[A-Z]'`
 changequote([,])dnl
-  AC_DEFINE(HAVE_${ac_tr_symbol})
+  AC_DEFINE_UNQUOTED(HAVE_${ac_tr_symbol})
 fi
 AC_MSG_RESULT($ac_cv_check_symbol_$1)])dnl