Bump Windows build numbers for 2.2a4; installer changes were done earlier.
diff --git a/PCbuild/BUILDno.txt b/PCbuild/BUILDno.txt
index 7d6938f..b0c65a3 100644
--- a/PCbuild/BUILDno.txt
+++ b/PCbuild/BUILDno.txt
@@ -33,6 +33,8 @@
 
 Windows Python BUILD numbers
 ----------------------------
+  24    2.2a4
+        28-Sep-2001
   23    2.2a3
         07-Sep-2001
   22    2.2a2