changes.src: begin documentation for 2.12.01

We probably ought to release 2.12.01 in the short term.  So far the
changes that have accumulated have all been build fixes.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/doc/changes.src b/doc/changes.src
index c6738b9..9f1c563 100644
--- a/doc/changes.src
+++ b/doc/changes.src
@@ -7,6 +7,12 @@
 The NASM 2 series supports x86-64, and is the production version of NASM
 since 2007.
 
+
+\S{cl-2.12.01} Version 2.12.01
+
+\b Portability fixes for some platforms.
+
+
 \S{cl-2.12} Version 2.12
 
 \b Major fixes to the \c{macho} backend (\k{machofmt}); earlier versions