SECURITY: Unbreak “set +p”, broken by OpenBSD ksh change.

TODO: I am seriously considering following Chet and changing
the way this works, by explicitly dropping privs unless the
shell is run with -p. Every other shell does it like mksh,
except Heirloom sh, which on the other hand doesn’t know any
explicit set -p or set +p (though it doesn’t know set +foo
for any foo either).

┌──┤ QUESTION: Do we need the ability to do this:
│ tg@blau:~ $ ./suidmksh -p -c 'whoami; set +p; whoami'
│ root
│ tg

If not, I’m seriously considering to drop set ±p as well,
only parse -p on the command line, with +p being the default,
and dropping FPRIVILEGED.

Thanks to RT for noticing and jilles for initial follow-up
discussion, as well as Chet Ramey for doing the sane/secure
thing instead of following Debian.

Build.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.645 2013/08/10 13:44:25 tg Exp $'
+srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.646 2013/08/23 14:07:32 tg Exp $'
 #-
 # Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
 #		2011, 2012, 2013
@@ -1598,7 +1598,7 @@ else
 		#define EXTERN
 		#define MKSH_INCLUDES_ONLY
 		#include "sh.h"
-		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.645 2013/08/10 13:44:25 tg Exp $");
+		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.646 2013/08/23 14:07:32 tg Exp $");
 		int main(void) { printf("Hello, World!\n"); return (0); }
 EOF
 	case $cm in
@@ -2113,7 +2113,7 @@ addsrcs USE_PRINTF_BUILTIN printf.c
 test 1 = "$USE_PRINTF_BUILTIN" && add_cppflags -DMKSH_PRINTF_BUILTIN
 test 1 = "$HAVE_CAN_VERB" && CFLAGS="$CFLAGS -verbose"
 test -n "$LDSTATIC" && add_cppflags -DMKSH_OPTSTATIC
-add_cppflags -DMKSH_BUILD_R=481
+add_cppflags -DMKSH_BUILD_R=483
 
 $e $bi$me: Finished configuration testing, now producing output.$ao