Change startup ABI for untrusted code to be C-compatible

src/trusted/service_runtime/nacl_config.h

Index: src/trusted/service_runtime/nacl_config.h
diff --git a/src/trusted/service_runtime/nacl_config.h b/src/trusted/service_runtime/nacl_config.h
index bf3cf509909d532611e8a588d803d5e5f48c4f3e..404db7f60ac27307ebbb0a259019ace9f33817c6 100644
--- a/src/trusted/service_runtime/nacl_config.h
+++ b/src/trusted/service_runtime/nacl_config.h
@@ -162,6 +162,8 @@
  * must do so here as well.
  */
 #  define NACL_STACK_ALIGN_MASK   (0xf)
+#  define NACL_STACK_GETS_ARG     (1)
+#  define NACL_STACK_PAD_BELOW_ALIGN (4)
 
 # elif NACL_BUILD_SUBARCH == 64
 #  define NACL_USERRET_FIX        (0x8)
@@ -173,6 +175,8 @@
  * 3.2.2 discusses stack alignment.
  */
 #  define NACL_STACK_ALIGN_MASK   (0xf)
+#  define NACL_STACK_GETS_ARG     (0)
+#  define NACL_STACK_PAD_BELOW_ALIGN (8)
 # else /* NACL_BUILD_SUBARCH */
 #  error Unknown platform!
 # endif /* NACL_BUILD_SUBARCH */
@@ -194,6 +198,8 @@
  * -- the "public" stack alignment is required to be 8 bytes,
  */
 # define NACL_STACK_ALIGN_MASK    (0x7)
+# define NACL_STACK_GETS_ARG      (0)
+# define NACL_STACK_PAD_BELOW_ALIGN (0)
 
 /* TODO(robertm): unify this with NACL_BLOCK_SHIFT */
 /* 16 byte bundles */