diff --git a/configure b/configure
index c01996aebe..e5a9b969cb 100755
--- a/configure
+++ b/configure
@@ -429,7 +429,7 @@ filter(){
     pat=$1
     shift
     for v; do
-        eval "case $v in $pat) echo $v ;; esac"
+        eval "case $v in $pat) printf '%s ' $v ;; esac"
     done
 }
 
@@ -437,7 +437,7 @@ filter_out(){
     pat=$1
     shift
     for v; do
-        eval "case $v in $pat) ;; *) echo $v ;; esac"
+        eval "case $v in $pat) ;; *) printf '%s ' $v ;; esac"
     done
 }