updated for version 7.3.029
Problem:    ":sort n" sorts lines without a number as number zero. (Beeyawned)
Solution:   Make lines without a number sort before lines with a number.  Also
            fix sorting negative numbers.
diff --git a/src/testdir/test57.ok b/src/testdir/test57.ok
index 1777133..aa3d373 100644
--- a/src/testdir/test57.ok
+++ b/src/testdir/test57.ok
@@ -21,6 +21,10 @@
 a
 
 
+
+-24
+x-22
+0
 a122
 a123
 b123