Disable use of tls scanning on darwin leak sanitizer

[fjricci]

Summary

These checks appear linux-specific, disable them on darwin, at
least for now.

[kubamracek]

I would slightly prefer to have a Linux/ subdirectory with Linux-specific tests. Are there more tests that will need to be skipped on Darwin? If not, the using UNSUPPORTED works as well.

[fjricci]

Yeah, there are a few more - tests using dlopen() without dlclose() and fork() without exec()

[fjricci]

I can combine all of those diffs into a single patch to move things to a new directory, and leave this one as just the code-change portion.

[fjricci]

Split out test component

compiler-rt/trunk/lib/lsan/lsan_common_mac.cc

 }
 
 void SetCurrentThread(u32 tid) { get_tls_val(true)->current_thread_id = tid; }
 
 AllocatorCache *GetAllocatorCache() { return &get_tls_val(true)->cache; }
 
 // Required on Linux for initialization of TLS behavior, but should not be
 // required on Darwin.
-void InitializePlatformSpecificModules() {}
+void InitializePlatformSpecificModules() {
+  if (flags()->use_tls) {
+    Report("use_tls=1 is not supported on Darwin.\n");
+    Die();
+  }
+}
 
 // Scans global variables for heap pointers.
 void ProcessGlobalRegions(Frontier *frontier) {
   MemoryMappingLayout memory_mapping(false);
   InternalMmapVector<LoadedModule> modules(/*initial_capacity*/ 128);
   memory_mapping.DumpListOfModules(&modules);
   for (uptr i = 0; i < modules.size(); ++i) {
     // Even when global scanning is disabled, we still need to scan

compiler-rt/trunk/lib/lsan/lsan_flags.inc

LSAN_FLAG(
     "zero, the entire stack trace must match.")
 LSAN_FLAG(int, max_leaks, 0, "The number of leaks reported.")
 
 // Flags controlling the root set of reachable memory.
 LSAN_FLAG(bool, use_globals, true,
           "Root set: include global variables (.data and .bss)")
 LSAN_FLAG(bool, use_stacks, true, "Root set: include thread stacks")
 LSAN_FLAG(bool, use_registers, true, "Root set: include thread registers")
-LSAN_FLAG(bool, use_tls, true,
+LSAN_FLAG(bool, use_tls, !SANITIZER_MAC,
           "Root set: include TLS and thread-specific storage")
 LSAN_FLAG(bool, use_root_regions, true,
           "Root set: include regions added via __lsan_register_root_region().")
 LSAN_FLAG(bool, use_ld_allocations, true,
           "Root set: mark as reachable all allocations made from dynamic "
           "linker. This was the old way to handle dynamic TLS, and will "
           "be removed soon. Do not use this flag.")
 
 LSAN_FLAG(bool, use_unaligned, false, "Consider unaligned pointers valid.")
 LSAN_FLAG(bool, use_poisoned, false,
           "Consider pointers found in poisoned memory to be valid.")
 LSAN_FLAG(bool, log_pointers, false, "Debug logging")
 LSAN_FLAG(bool, log_threads, false, "Debug logging")
 LSAN_FLAG(const char *, suppressions, "", "Suppressions file name.")