[tsan] Skip building libcxx_tsan on OS X

[kubamracek]

Summary

The TSan-instrumented version of libcxx doesn't even build on OS X at this point. Let's skip it from the OS X build for now, since most of TSan functionality doesn't depend on it. This will enable check-tsan to be run.

[ismailp]

Hi Kuba,

Did it fail to compile or link? I haven't tried it after rebasing my branch on top of your commits, but I believe it can build.

compiler-rt/trunk/test/tsan/CMakeLists.txt

 set(TSAN_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
 if(NOT ${COMPILER_RT_DEFAULT_TARGET_ARCH} MATCHES "mips" AND NOT APPLE)
   list(APPEND TSAN_TEST_DEPS GotsanRuntimeCheck)
 endif()
 if(NOT COMPILER_RT_STANDALONE_BUILD)
   list(APPEND TSAN_TEST_DEPS tsan)
 endif()
 if(COMPILER_RT_HAS_LIBCXX_SOURCES AND
-   COMPILER_RT_TEST_COMPILER_ID STREQUAL "Clang")
+   COMPILER_RT_TEST_COMPILER_ID STREQUAL "Clang"
+   AND NOT APPLE)
   list(APPEND TSAN_TEST_DEPS libcxx_tsan)
   set(TSAN_HAS_LIBCXX True)
 else()
   set(TSAN_HAS_LIBCXX False)
 endif()
 
 configure_lit_site_cfg(
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in