diff --git a/doc/Jamfile b/doc/Jamfile
index 406e7cee..d7461771 100644
--- a/doc/Jamfile
+++ b/doc/Jamfile
@@ -94,7 +94,7 @@ else
     {
         export LIB_DIR=$(2:B=:S=..)
         export XML_OUTPUT=$(1:D)
-        echo "LIB_DIR=$LIB_DIR" > $(LIB_DIR)/doc/html/lib_dir.txt
+        echo "LIB_DIR=$LIB_DIR" > "$LIB_DIR/doc/html/lib_dir.txt"
         "$(.doxygen)" $(2)
     }
 }