kern/50312: current kernel compile failure if PAX_ASLR is not defined

[kre%munnari.OZ.AU@localhost]

>Number:         50312
>Category:       kern
>Synopsis:       current kernel compile failure if PAX_ASLR is not defined
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Oct 08 01:25:00 +0000 2015
>Originator:     Robert Elz
>Release:        NetBSD 7.99.21  (current as of 2015-10-08)
>Organization:
	Prince of Songkla University
>Environment:
System: NetBSD andromeda.noi.kre.to 7.0_RC2 NetBSD 7.0_RC2 (VBOX64-1.1-20150727) #12: Mon Jul 27 11:21:03 ICT 2015 kre%onyx.coe.psu.ac.th@localhost:/usr/obj/7/kernels/amd64/VBOX64 amd64
Architecture: x86_64
Machine: amd64
>Description:
	If a kernel configuration file does not have the PAX_ASLR option
	in it at all, the resulting kernel fails to compile.

	The problem is in kern_pax.c ...

/release/current/src/sys/kern/kern_pax.c: In function 'pax_setup_elf_flags':
/release/current/src/sys/kern/kern_pax.c:308:5: error: dereferencing pointer to 
incomplete type
  epp->ep_pax_flags = flags;
     ^

	To make it easier to find, the line in question is the last
	meaningful line in pax_setup_elf_flags()

	epp is a struct exec_package *

	struct exec_package is defined in sys/exec.h

	kern_pax.c includes sys/exec.h only if PAX_ASLR is defined.

	Line 308 of kern_pax.c is compiled, regardless of whether
	PAX_ASLR is defined or not.    If not there's no definition
	visible of struct exec_package (there are declarations,
	just not the definition) so ...

>How-To-Repeat:
	(Attempt to) Build a current kernel that does not PAX_ASLR
	in its config file.

>Fix:
	Not sure .. either unconditionally include sys/exec.h
	or #ifdef the line in question, or maybe something different.