c-index-test/Makefile: Add clangFormat to USEDLIBS for libclang-unavailable hosts.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170693 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/c-index-test/Makefile b/tools/c-index-test/Makefile
index 71efe34..1171954 100644
--- a/tools/c-index-test/Makefile
+++ b/tools/c-index-test/Makefile
@@ -24,6 +24,7 @@
 
 LINK_COMPONENTS := $(TARGETS_TO_BUILD) asmparser support mc
 USEDLIBS = clang.a \
+	   clangFormat.a clangRewriteCore.a \
 	   clangFrontend.a clangDriver.a \
 	   clangTooling.a \
 	   clangSerialization.a clangParse.a clangSema.a \