Index: libcxx/trunk/CMakeLists.txt
===================================================================
--- libcxx/trunk/CMakeLists.txt
+++ libcxx/trunk/CMakeLists.txt
@@ -352,6 +352,13 @@
 endif()
 file(MAKE_DIRECTORY "${LIBCXX_BINARY_INCLUDE_DIR}")
 
+set(LIBCXX_INSTALL_PREFIX "" CACHE STRING
+    "Define libc++ destination prefix.")
+
+if (NOT LIBCXX_INSTALL_PREFIX MATCHES "^$|.*/")
+  message(FATAL_ERROR "LIBCXX_INSTALL_PREFIX has to end with \"/\".")
+endif()
+
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR})
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR})
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR})
Index: libcxx/trunk/cmake/Modules/HandleLibCXXABI.cmake
===================================================================
--- libcxx/trunk/cmake/Modules/HandleLibCXXABI.cmake
+++ libcxx/trunk/cmake/Modules/HandleLibCXXABI.cmake
@@ -55,7 +55,7 @@
           )
         if (LIBCXX_INSTALL_HEADERS)
           install(FILES "${LIBCXX_BINARY_INCLUDE_DIR}/${fpath}"
-            DESTINATION include/c++/v1/${dstdir}
+            DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1/${dstdir}
             COMPONENT libcxx
             PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
             )
Index: libcxx/trunk/docs/BuildingLibcxx.rst
===================================================================
--- libcxx/trunk/docs/BuildingLibcxx.rst
+++ libcxx/trunk/docs/BuildingLibcxx.rst
@@ -216,6 +216,11 @@
   Extra suffix to append to the directory where libraries are to be installed.
   This option overrides `LLVM_LIBDIR_SUFFIX`.
 
+.. option:: LIBCXX_INSTALL_PREFIX:STRING
+
+  **Default**: ``""``
+
+  Define libc++ destination prefix.
 
 .. _libc++experimental options:
 
Index: libcxx/trunk/include/CMakeLists.txt
===================================================================
--- libcxx/trunk/include/CMakeLists.txt
+++ libcxx/trunk/include/CMakeLists.txt
@@ -20,7 +20,7 @@
 
 if (LIBCXX_INSTALL_HEADERS)
   install(DIRECTORY .
-    DESTINATION include/c++/v1
+    DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1
     COMPONENT cxx-headers
     FILES_MATCHING
     ${LIBCXX_HEADER_PATTERN}
@@ -44,7 +44,7 @@
     set(generated_config_deps generate_config_header)
     # Install the generated header as __config.
     install(FILES ${LIBCXX_BINARY_DIR}/__generated_config
-      DESTINATION include/c++/v1
+      DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1
       PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
       RENAME __config
       COMPONENT cxx-headers)
Index: libcxx/trunk/lib/CMakeLists.txt
===================================================================
--- libcxx/trunk/lib/CMakeLists.txt
+++ libcxx/trunk/lib/CMakeLists.txt
@@ -355,8 +355,8 @@
     set(experimental_lib cxx_experimental)
   endif()
   install(TARGETS ${LIBCXX_TARGETS} ${experimental_lib}
-    LIBRARY DESTINATION lib${LIBCXX_LIBDIR_SUFFIX} COMPONENT cxx
-    ARCHIVE DESTINATION lib${LIBCXX_LIBDIR_SUFFIX} COMPONENT cxx
+    LIBRARY DESTINATION ${LIBCXX_INSTALL_PREFIX}lib${LIBCXX_LIBDIR_SUFFIX} COMPONENT cxx
+    ARCHIVE DESTINATION ${LIBCXX_INSTALL_PREFIX}lib${LIBCXX_LIBDIR_SUFFIX} COMPONENT cxx
     )
   # NOTE: This install command must go after the cxx install command otherwise
   # it will not be executed after the library symlinks are installed.
@@ -364,7 +364,7 @@
     # Replace the libc++ filename with $<TARGET_LINKER_FILE:cxx>
     # after we required CMake 3.0.
     install(FILES "${LIBCXX_LIBRARY_DIR}/libc++${CMAKE_SHARED_LIBRARY_SUFFIX}"
-      DESTINATION lib${LIBCXX_LIBDIR_SUFFIX}
+      DESTINATION ${LIBCXX_INSTALL_PREFIX}lib${LIBCXX_LIBDIR_SUFFIX}
       COMPONENT libcxx)
   endif()
 endif()