tlsdate: add SECCOMP_AUDIT_ARCH definition for MIPS

BUG=chromium:416748
TEST=`USE=seccomp emerge-{x86,amd64,arm,mipsel-o32}-generic tlsdate`

Change-Id: Ie50b4739aa35042d9a322c05c8d1b6875f14ee4a
Reviewed-on: https://chromium-review.googlesource.com/219419
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
diff --git a/src/seccomp.c b/src/seccomp.c
index bc25e4c..8ce0967 100644
--- a/src/seccomp.c
+++ b/src/seccomp.c
@@ -44,10 +44,24 @@
 #elif defined(__x86_64__)
 #  define SECCOMP_AUDIT_ARCH AUDIT_ARCH_X86_64
 #elif defined(__arm__)
-# ifndef EM_ARM
-#   define EM_ARM 40
-# endif
+#  ifndef EM_ARM
+#    define EM_ARM 40
+#  endif
 #  define SECCOMP_AUDIT_ARCH AUDIT_ARCH_ARM
+#elif defined(__mips__)
+#  if defined(__mips64)
+#    if defined(__MIPSEB__)
+#      define SECCOMP_AUDIT_ARCH AUDIT_ARCH_MIPS64
+#    else
+#      define SECCOMP_AUDIT_ARCH AUDIT_ARCH_MIPSEL64
+#    endif
+#  else
+#    if defined(__MIPSEB__)
+#      define SECCOMP_AUDIT_ARCH AUDIT_ARCH_MIPS
+#    else
+#      define SECCOMP_AUDIT_ARCH AUDIT_ARCH_MIPSEL
+#    endif
+#  endif
 #else
 #  error "Platform does not support seccomp filter yet"
 #endif