[Bug target/52268] tls support should be added for darwin11

[howarth at nitro dot med.uc.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52268

--- Comment #3 from Jack Howarth <howarth at nitro dot med.uc.edu> 2012-02-29 
17:18:19 UTC ---
Also in clang 3.0, I see test/CodeGen/darwin-thread-specifier.c which
contains...

// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.0 -emit-llvm -o - %s |
FileCheck %s
// CHECK: @b = thread_local global i32 5, align 4
__thread int b = 5;

whereas their test/CodeGen/thread-specifier.c has...

// RUN: %clang_cc1 -triple i686-pc-linux-gnu -emit-llvm -o - %s | FileCheck %s

// CHECK: @b = external thread_local global
// CHECK: @d.e = internal thread_local global
// CHECK: @d.f = internal thread_local global
// CHECK: @a = thread_local global
__thread int a;
extern __thread int b;
int c() { return *&b; }
int d() {
  __thread static int e;
  __thread static union {float a; int b;} f = {.b = 1};
  return 0;
}