[libcxx] Add "install-libcxx" target.

Summary: Currently you can't install libc++ from within the LLVM tree without installing all of LLVM. This patch adds an install rule for libc++.

Reviewers: mclow.lists, danalbert, jroelofs, EricWF

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D11697

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@245470 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 26dee67..0c83f05 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -134,6 +134,14 @@
   )
 
 install(TARGETS cxx
-  LIBRARY DESTINATION lib${LIBCXX_LIBDIR_SUFFIX}
-  ARCHIVE DESTINATION lib${LIBCXX_LIBDIR_SUFFIX}
+  LIBRARY DESTINATION lib${LIBCXX_LIBDIR_SUFFIX} COMPONENT libcxx
+  ARCHIVE DESTINATION lib${LIBCXX_LIBDIR_SUFFIX} COMPONENT libcxx
   )
+
+if (NOT CMAKE_CONFIGURATION_TYPES)
+  add_custom_target(install-libcxx
+                    DEPENDS cxx
+                    COMMAND "${CMAKE_COMMAND}"
+                    -DCMAKE_INSTALL_COMPONENT=libcxx
+                    -P "${LIBCXX_BINARY_DIR}/cmake_install.cmake")
+endif()