[libc++abi] Link against libSystem on Apple platforms

On Apple platforms, libSystem is an umbrella for all other system
libraries, and libpthread (and friends) are actually just symlinks
to libSystem.

llvm-svn: 373770

diff --git a/libcxxabi/cmake/config-ix.cmake b/libcxxabi/cmake/config-ix.cmake
index 94f89be..496ed34 100644 (file)
--- a/libcxxabi/cmake/config-ix.cmake
+++ b/libcxxabi/cmake/config-ix.cmake
@@ -75,3 +75,4 @@ check_library_exists(dl dladdr "" LIBCXXABI_HAS_DL_LIB)
 check_library_exists(pthread pthread_once "" LIBCXXABI_HAS_PTHREAD_LIB)
 check_library_exists(c __cxa_thread_atexit_impl ""
   LIBCXXABI_HAS_CXA_THREAD_ATEXIT_IMPL)
+check_library_exists(System write "" LIBCXXABI_HAS_SYSTEM_LIB)

diff --git a/libcxxabi/src/CMakeLists.txt b/libcxxabi/src/CMakeLists.txt
index 6cfcb9c..cbf4b21 100644 (file)
--- a/libcxxabi/src/CMakeLists.txt
+++ b/libcxxabi/src/CMakeLists.txt
@@ -60,11 +60,16 @@ if (LIBCXXABI_HAS_CXA_THREAD_ATEXIT_IMPL)
   add_definitions(-DHAVE___CXA_THREAD_ATEXIT_IMPL)
 endif()
 
-if (LIBCXXABI_ENABLE_THREADS)
-  add_library_flags_if(LIBCXXABI_HAS_PTHREAD_LIB pthread)
+if (APPLE)
+  add_library_flags_if(LIBCXXABI_HAS_SYSTEM_LIB System)
+else()
+  if (LIBCXXABI_ENABLE_THREADS)
+    add_library_flags_if(LIBCXXABI_HAS_PTHREAD_LIB pthread)
+  endif()
+
+  add_library_flags_if(LIBCXXABI_HAS_C_LIB c)
 endif()
 
-add_library_flags_if(LIBCXXABI_HAS_C_LIB c)
 if (LIBCXXABI_USE_LLVM_UNWINDER)
   # Prefer using the in-tree version of libunwind, either shared or static. If
   # none are found fall back to using -lunwind.