[clang] Use add_llvm_install_targets

Use this function to create the install targets rather than doing so
manually, which gains us the `-stripped` install targets to perform
stripped installations.

Differential Revision: https://reviews.llvm.org/D40675

llvm-svn: 319489
diff --git a/clang/tools/c-index-test/CMakeLists.txt b/clang/tools/c-index-test/CMakeLists.txt
index ad990e0..c5cb059 100644
--- a/clang/tools/c-index-test/CMakeLists.txt
+++ b/clang/tools/c-index-test/CMakeLists.txt
@@ -56,10 +56,8 @@
     COMPONENT c-index-test)
 
   if (NOT CMAKE_CONFIGURATION_TYPES) # don't add this for IDE's.
-    add_custom_target(install-c-index-test
-      DEPENDS c-index-test
-      COMMAND "${CMAKE_COMMAND}"
-              -DCMAKE_INSTALL_COMPONENT=c-index-test
-              -P "${CMAKE_BINARY_DIR}/cmake_install.cmake")
+    add_llvm_install_targets(install-c-index-test
+                             DEPENDS c-index-test
+                             COMPONENT c-index-test)
   endif()
 endif()