man: Fix and update Arch substvar description in deb-substvars(5)

debian/changelog

@@ -9,6 +9,7 @@ dpkg (1.18.0) UNRELEASED; urgency=low
     messages. Closes: #773398
   * Document when and how the dpkg-maintscript-helper package name argument
     is or should be arch-qualified. Closes: #776072
+  * Fix and update Arch substvar description in deb-substvars(5).
 
  -- Guillem Jover <guillem@debian.org>  Tue, 09 Dec 2014 23:53:18 +0100
 

man/deb-substvars.5

@@ -2,6 +2,7 @@
 .\"
 .\" Copyright © 1995-1996 Ian Jackson <ian@chiark.chu.cam.ac.uk>
 .\" Copyright © 2000 Wichert Akkerman <wakkerma@debian.org>
+.\" Copyright © 2006-2009,2012-2015 Guillem Jover <guillem@debian.org>
 .\" Copyright © 2009-2010 Raphaël Hertzog <hertzog@debian.org>
 .\"
 .\" This is free software; you can redistribute it and/or modify
@@ -90,8 +91,8 @@ symbol (comments) are ignored.
 Additionally, the following standard variables are available:
 .TP
 .BI Arch
-The current build architecture (from
-.BR "dpkg \-\-print\-architecture" ).
+The current host architecture (i.e. the architecture the package is being
+built for, the equivalent of \fBDEB_HOST_ARCH\fP).
 .TP
 .B source:Version
 The source package version.