Fix installation of cxxabi.h through libc++.

Previously, the install command for the cxxabi headers specified
the wrong component, and therefore they were not being included
in the install-cxx command.

This patch corrects the component name.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@318989 91177308-0d34-0410-b5e6-96231b3b80d8

cmake/Modules/HandleLibCXXABI.cmake

@@ -56,7 +56,7 @@ macro(setup_abi_lib abidefines abilib abifiles abidirs)
         if (LIBCXX_INSTALL_HEADERS)
           install(FILES "${LIBCXX_BINARY_INCLUDE_DIR}/${fpath}"
             DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1/${dstdir}
-            COMPONENT libcxx
+            COMPONENT cxx-headers
             PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
             )
         endif()