Roll back r318260 because it is causing the windows bot to

break.  The alignas(__uint128_t) is not recognized with MSVC
it looks like.  Zachary, is there a similar type on windows?
I suppose I can go with alignas(16) here but I'd prefer to
specify the type alignment that I want & let the ABI dictate
how much padding is required.

llvm-svn: 318262

lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp

@@ -686,7 +686,7 @@ public:
       case FPURegSet: {
         uint8_t *fpu_reg_buf = (uint8_t *)&fpu.v[0];
         const int fpu_reg_buf_size = sizeof(fpu);
-        if (fpu_reg_buf_size == count * sizeof(uint32_t) &&
+        if (fpu_reg_buf_size == count &&
             data.ExtractBytes(offset, fpu_reg_buf_size, eByteOrderLittle,
                               fpu_reg_buf) == fpu_reg_buf_size) {
           SetError(FPURegSet, Read, 0);

lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.h

@@ -83,7 +83,7 @@ public:
 
   // mirrors <mach/arm/thread_status.h> arm_neon_state64_t
   struct FPU {
-    alignas(__uint128_t) VReg v[32];
+    VReg v[32];
     uint32_t fpsr;
     uint32_t fpcr;
   };