Add a -p option which is the same as the -m option but provided

for SVR4 compatibility.

PR:		5826

usr.bin/uname/uname.1

@@ -39,7 +39,7 @@
 .Nd display information about the system
 .Sh SYNOPSIS
 .Nm
-.Op Fl amnrsv
+.Op Fl amnprsv
 .Sh DESCRIPTION
 The
 .Nm
@@ -63,6 +63,10 @@ were specified.
 Write the type of the current hardware platform to standard output.
 .It Fl n
 Write the name of the system to standard output.
+.It Fl p
+Writes out the same value as
+.Fl m .
+This option is provided for backward compatibility with SVR4.
 .It Fl r
 Write the current release level of the operating system
 to standard output.

usr.bin/uname/uname.c

@@ -67,11 +67,12 @@ main(argc, argv)
 	char *p, *prefix, buf[1024];
 
 	flags = 0;
-	while ((ch = getopt(argc, argv, "amnrsv")) != -1)
+	while ((ch = getopt(argc, argv, "amnprsv")) != -1)
 		switch(ch) {
 		case 'a':
 			flags |= (MFLAG | NFLAG | RFLAG | SFLAG | VFLAG);
 			break;
+		case 'p':
 		case 'm':
 			flags |= MFLAG;
 			break;