Index: libcxx/trunk/CMakeLists.txt
===================================================================
--- libcxx/trunk/CMakeLists.txt
+++ libcxx/trunk/CMakeLists.txt
@@ -386,7 +386,6 @@
 set(LIBCXX_COMPILER    ${CMAKE_CXX_COMPILER})
 set(LIBCXX_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})
 set(LIBCXX_BINARY_DIR  ${CMAKE_CURRENT_BINARY_DIR})
-set(LIBCXX_HEADER_DIR  ${LLVM_BINARY_DIR})
 set(LIBCXX_BINARY_INCLUDE_DIR "${LIBCXX_BINARY_DIR}/include/c++build")
 
 string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION
@@ -399,8 +398,10 @@
   set(LIBCXX_HEADER_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION})
 elseif(LLVM_LIBRARY_OUTPUT_INTDIR)
   set(LIBCXX_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
+  set(LIBCXX_HEADER_DIR  ${LLVM_BINARY_DIR})
 else()
   set(LIBCXX_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX})
+  set(LIBCXX_HEADER_DIR  ${CMAKE_BINARY_DIR})
 endif()
 
 file(MAKE_DIRECTORY "${LIBCXX_BINARY_INCLUDE_DIR}")
Index: libcxx/trunk/cmake/Modules/HandleLibCXXABI.cmake
===================================================================
--- libcxx/trunk/cmake/Modules/HandleLibCXXABI.cmake
+++ libcxx/trunk/cmake/Modules/HandleLibCXXABI.cmake
@@ -48,12 +48,14 @@
             COMMENT "Copying C++ ABI header ${fpath}...")
         list(APPEND abilib_headers "${dst}")
 
-        set(dst "${LIBCXX_HEADER_DIR}/include/c++/v1/${dstdir}/${fpath}")
-        add_custom_command(OUTPUT ${dst}
-            DEPENDS ${src}
-            COMMAND ${CMAKE_COMMAND} -E copy_if_different ${src} ${dst}
-            COMMENT "Copying C++ ABI header ${fpath}...")
-        list(APPEND abilib_headers "${dst}")
+        if (NOT LIBCXX_USING_INSTALLED_LLVM)
+          set(dst "${LIBCXX_HEADER_DIR}/include/c++/v1/${dstdir}/${fpath}")
+          add_custom_command(OUTPUT ${dst}
+              DEPENDS ${src}
+              COMMAND ${CMAKE_COMMAND} -E copy_if_different ${src} ${dst}
+              COMMENT "Copying C++ ABI header ${fpath}...")
+          list(APPEND abilib_headers "${dst}")
+        endif()
 
         if (LIBCXX_INSTALL_HEADERS)
           install(FILES "${LIBCXX_BINARY_INCLUDE_DIR}/${fpath}"