diff --git a/lld/CMakeLists.txt b/lld/CMakeLists.txt
--- a/lld/CMakeLists.txt
+++ b/lld/CMakeLists.txt
@@ -110,6 +110,10 @@
       set(LLVM_INCLUDE_TESTS OFF)
     endif()
   endif()
+
+  if(HAVE_LIBXAR)
+    set(XAR_LIB xar)
+  endif()
 endif()
 
 set(LLD_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/lld/MachO/CMakeLists.txt b/lld/MachO/CMakeLists.txt
--- a/lld/MachO/CMakeLists.txt
+++ b/lld/MachO/CMakeLists.txt
@@ -48,6 +48,7 @@
   LINK_LIBS
   lldCommon
   ${LLVM_PTHREAD_LIB}
+  ${XAR_LIB}
 
   DEPENDS
   MachOOptionsTableGen
diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -31,7 +31,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/MachO.h"
 #include "llvm/BinaryFormat/Magic.h"
-#include "llvm/Config/config.h"
+#include "llvm/Config/llvm-config.h"
 #include "llvm/LTO/LTO.h"
 #include "llvm/Object/Archive.h"
 #include "llvm/Option/ArgList.h"
diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp
--- a/lld/MachO/SyntheticSections.cpp
+++ b/lld/MachO/SyntheticSections.cpp
@@ -20,7 +20,7 @@
 #include "lld/Common/ErrorHandler.h"
 #include "lld/Common/Memory.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/Config/config.h"
+#include "llvm/Config/llvm-config.h"
 #include "llvm/Support/EndianStream.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/LEB128.h"
diff --git a/llvm/cmake/modules/LLVMConfig.cmake.in b/llvm/cmake/modules/LLVMConfig.cmake.in
--- a/llvm/cmake/modules/LLVMConfig.cmake.in
+++ b/llvm/cmake/modules/LLVMConfig.cmake.in
@@ -111,6 +111,8 @@
 set(LLVM_DEFAULT_EXTERNAL_LIT "@LLVM_CONFIG_DEFAULT_EXTERNAL_LIT@")
 set(LLVM_LIT_ARGS "@LLVM_LIT_ARGS@")
 
+set(HAVE_LIBXAR "@HAVE_LIBXAR")
+
 if(NOT TARGET LLVMSupport)
   set(LLVM_EXPORTED_TARGETS "@LLVM_CONFIG_EXPORTS@")
   include("@LLVM_CONFIG_EXPORTS_FILE@")
diff --git a/llvm/include/llvm/Config/config.h.cmake b/llvm/include/llvm/Config/config.h.cmake
--- a/llvm/include/llvm/Config/config.h.cmake
+++ b/llvm/include/llvm/Config/config.h.cmake
@@ -220,9 +220,6 @@
 /* Define if the setupterm() function is supported this platform. */
 #cmakedefine LLVM_ENABLE_TERMINFO ${LLVM_ENABLE_TERMINFO}
 
-/* Define if the xar_open() function is supported this platform. */
-#cmakedefine HAVE_LIBXAR ${HAVE_LIBXAR}
-
 /* Define to 1 if you have the <termios.h> header file. */
 #cmakedefine HAVE_TERMIOS_H ${HAVE_TERMIOS_H}
 
diff --git a/llvm/include/llvm/Config/llvm-config.h.cmake b/llvm/include/llvm/Config/llvm-config.h.cmake
--- a/llvm/include/llvm/Config/llvm-config.h.cmake
+++ b/llvm/include/llvm/Config/llvm-config.h.cmake
@@ -94,4 +94,7 @@
 /* Define to 1 to enable the experimental new pass manager by default */
 #cmakedefine01 LLVM_ENABLE_NEW_PASS_MANAGER
 
+/* Define if the xar_open() function is supported on this platform. */
+#cmakedefine HAVE_LIBXAR ${HAVE_LIBXAR}
+
 #endif