Mention the environment variables that affect the execution of uniq.

Of particular interest is the fact that LC_COLLATE affects how uniq
determines whether lines are equal. This was the subject of a fairly heated
debate a year or so ago, and it turns out that the current behaviour is
correct and that the standard contained an error.

Now that the standard has been corrected by Cor. 1-2002, refer to 1003.1-2001
instead of the 1992 edition in the Standards section.

usr.bin/uniq/uniq.1

@@ -35,7 +35,7 @@
 .\"     From: @(#)uniq.1	8.1 (Berkeley) 6/6/93
 .\" $FreeBSD$
 .\"
-.Dd June 6, 1993
+.Dd April 12, 2003
 .Dt UNIQ 1
 .Os
 .Sh NAME
@@ -121,6 +121,17 @@ Case insensitive comparison of lines.
 .\"is a
 .\"number.
 .El
+.Sh ENVIRONMENT
+The
+.Ev LANG ,
+.Ev LC_ALL ,
+.Ev LC_COLLATE
+and
+.Ev LC_CTYPE
+environment variables affect the execution of
+.Nm
+as described in
+.Xr environ 7 .
 .Sh DIAGNOSTICS
 .Ex -std
 .Sh COMPATIBILITY
@@ -134,9 +145,9 @@ options have been deprecated but are still supported in this implementation.
 .Sh STANDARDS
 The
 .Nm
-utility is expected to be
-.St -p1003.2
-compatible.
+utility conforms to
+.St -p1003.1-2001
+as amended by Cor. 1-2002.
 .Sh HISTORY
 A
 .Nm