man: Document environment variables affecting dpkg-deb, dpkg and dselect

The missing undocumented variables are TMPDIR for dpkg and dpkg-deb,
HOME for dselect and dpkg and PAGER for dpkg.

Closes: #572836

debian/changelog

@@ -158,6 +158,8 @@ dpkg (1.15.6) UNRELEASED; urgency=low
     guarantees when doing rename(2). Based on a patch by
     Jean-Baptiste Lallement <jeanbaptiste.lallement@gmail.com>.
     Closes: #430958
+  * Document in the man page the effects of setting TMPDIR for dpkg and
+    dpkg-deb, HOME for dselect and dpkg and PAGER for dpkg. Closes: #572836
 
   [ Modestas Vainius ]
   * Implement symbol patterns (Closes: #563752). From now on, it is possible to

man/dpkg-deb.1

@@ -1,4 +1,4 @@
-.TH dpkg\-deb 1 "2009-01-07" "Debian Project" "dpkg suite"
+.TH dpkg\-deb 1 "2010-03-07" "Debian Project" "dpkg suite"
 .SH NAME
 dpkg\-deb \- Debian package archive (.deb) manipulation tool
 .
@@ -216,6 +216,12 @@ any archive you want, no matter how broken, this way.
 .BR \-D ", " \-\-debug
 Enables debugging output. This is not very interesting.
 .
+.SH ENVIRONMENT
+.TP
+.B TMPDIR
+If set, \fBdpkg\-deb\fP will use it as the directory in which to create
+temporary files and directories.
+.
 .SH BUGS
 .B dpkg\-deb \-I
 .IB package1 .deb

man/dpkg.1

@@ -1,4 +1,4 @@
-.TH dpkg 1 "2010-02-20" "Debian Project" "dpkg suite"
+.TH dpkg 1 "2010-03-07" "Debian Project" "dpkg suite"
 .SH NAME
 dpkg \- package manager for Debian
 .
@@ -610,6 +610,17 @@ for more information about them:
 .
 .SH ENVIRONMENT VARIABLES
 .TP
+.B HOME
+If set, \fBdpkg\fP will use it as the directory from which to read the user
+specific configuration file.
+.TP
+.B TMPDIR
+If set, \fBdpkg\fP will use it as the directory in which to create
+temporary files and directories.
+.TP
+.B PAGER
+The program \fBdpkg\fP will execute when displaying the conffiles.
+.TP
 .B SHELL
 The program \fBdpkg\fP will execute when starting a new shell.
 .TP

man/dselect.1

@@ -1,4 +1,4 @@
-.TH dselect 1 "2009-08-20" "Debian Project" "Debian"
+.TH dselect 1 "2010-03-07" "Debian Project" "Debian"
 .SH NAME
 dselect \- Debian package management frontend
 .
@@ -427,6 +427,12 @@ but provides a more obvious panic button in cases where the user
 pressed \fBenter\fP by accident.
 .sp
 .
+.SH ENVIRONMENT
+.TP
+.B HOME
+If set, \fBdselect\fP will use it as the directory from which to read the
+user specific configuration file.
+.
 .SH BUGS
 The
 .B dselect