-e option isn't available on all echo

extras/contrib/bootstrap

@@ -41,7 +41,10 @@ else
 fi
 
 rm -f config.mak
-echo -e "# Automatically generated by bootstrap.\n# Make changes if you know what you're doing.\n" > config.mak
+{
+    echo "# Automatically generated by bootstrap."
+    echo "# Make changes if you know what you're doing."
+} > config.mak
 
 if test "$HOST" != "$BUILD"; then
     CC="${HOST}-gcc"