'#' is not a comment if a non-space char follow

Closes PR # bin/657: mail(1): comments in ~/.ma...

Submitted by:	wosch@cs.tu-berlin.de (Wolfram Schneider)

usr.bin/mail/lex.c

@@ -458,6 +458,17 @@ lex(word)
 	register struct cmd *cp;
 	extern struct cmd cmdtab[];
 
+	/*
+	 * ignore trailing chars after `#' 
+	 *
+	 * lines with beginning `#' are comments
+	 * spaces befor `#' are ignored in execute()
+	 */
+
+	if (*word == '#')
+	    *(word+1) = '\0';
+
+
 	for (cp = &cmdtab[0]; cp->c_name != NOSTR; cp++)
 		if (isprefix(word, cp->c_name))
 			return(cp);

usr.bin/mail/mail.1

@@ -308,6 +308,8 @@ argument
 goes to the
 .Ar n Ns 'th
 previous message and prints it.
+.It Ic \&#
+ignore the remainder of the line as a comment.
 .It Ic \&?
 Prints a brief summary of commands.
 .It Ic \&!