Expose LLC's -force-align-stack flag to pnacl-translate

tests/toolchain/call_with_misaligned_stack.S

Index: tests/toolchain/call_with_misaligned_stack.S
diff --git a/tests/toolchain/call_with_misaligned_stack.S b/tests/toolchain/call_with_misaligned_stack.S
new file mode 100644
index 0000000000000000000000000000000000000000..7727f3e5c8d85e50c244934997f9ac25f62d79cc
--- /dev/null
+++ b/tests/toolchain/call_with_misaligned_stack.S
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2014 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * Call the argument with a stack pointer 4 bytes below its value on entry.
+ * This will ensure that (assuming it's aligned on a 16-byte boundary on entry)
+ * it will be misaligned on entry to the callee.
+*/
+    .text
+    .p2align 5
+    .globl   call_with_misaligned_stack
+    .type    call_with_misaligned_stack, @function
+call_with_misaligned_stack:
+    movl     4(%esp), %ecx   /* call target */
+    naclcall %ecx
+    pop      %ecx
+    nacljmp  %ecx
+    .p2align 5