WIP: Implement seccomp-bpf sandbox for nacl_helper_nonsfi.

sandbox/linux/bpf_dsl/seccomp_macros.h

Index: sandbox/linux/bpf_dsl/seccomp_macros.h
diff --git a/sandbox/linux/bpf_dsl/seccomp_macros.h b/sandbox/linux/bpf_dsl/seccomp_macros.h
index 7fd0e67f1a55fea062a3762565f254074ae24ce6..d4d5b82498ca3fce26d8a2639a1793e31bf29f4d 100644
--- a/sandbox/linux/bpf_dsl/seccomp_macros.h
+++ b/sandbox/linux/bpf_dsl/seccomp_macros.h
@@ -5,16 +5,16 @@
 #ifndef SANDBOX_LINUX_BPF_DSL_SECCOMP_MACROS_H_
 #define SANDBOX_LINUX_BPF_DSL_SECCOMP_MACROS_H_
 
-#include <asm/unistd.h>
-#include <linux/filter.h>
+#include "build/build_config.h"
 
-#include <sys/cdefs.h>
 // Old Bionic versions do not have sys/user.h.  The if can be removed once we no
 // longer need to support these old Bionic versions.
 // All x86_64 builds use a new enough bionic to have sys/user.h.
 #if !defined(__BIONIC__) || defined(__x86_64__)
 #include <sys/types.h>  // Fix for gcc 4.7, make sure __uint16_t is defined.
+#if !defined(OS_NACL_NONSFI)
 #include <sys/user.h>
+#endif
 #if defined(__mips__)
 // sys/user.h in eglibc misses size_t definition
 #include <stddef.h>
@@ -53,10 +53,10 @@
                                  8*(nr) + 0)
 
 
-#if defined(__BIONIC__)
-// Old Bionic versions don't have sys/user.h, so we just define regs_struct
-// directly.  This can be removed once we no longer need to support these old
-// Bionic versions.
+#if defined(__BIONIC__) || defined(OS_NACL_NONSFI)
+// Old Bionic versions and PNaCl toolchain for nacl_helper_nonsfi don't have
+// sys/user.h, so we just define regs_struct directly.  This can be removed
+// once we no longer need to support these old Bionic versions.
 struct regs_struct {
   long int ebx;
   long int ecx;