Work around an ARM EABI issue where clang would sometimes incorrectly align

the stack in a leaf function that uses TLS.

The issue is, when using TLS, the function is no longer a leaf as it calls
__aeabi_read_tp. With statically linked programs this is not an issue as
it doesn't make use of the stack, however with dynamically linked
applications we enter rtld which does use the stack and makes assumptions
about it's alignment.

This is only a temporary fix until a better patch can be made and submitted
upstream.

contrib/llvm/lib/Target/ARM/ARMFrameLowering.h

@@ -27,7 +27,7 @@ class ARMFrameLowering : public TargetFrameLowering {
 
 public:
   explicit ARMFrameLowering(const ARMSubtarget &sti)
-    : TargetFrameLowering(StackGrowsDown, sti.getStackAlignment(), 0, 4),
+    : TargetFrameLowering(StackGrowsDown, sti.getStackAlignment(), 0, 8),
       STI(sti) {
   }