c-index-test/Makefile: Tweak USEDLIBS for cygwin. cygclang.dll is not linked to c-index-test yet.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159499 91177308-0d34-0410-b5e6-96231b3b80d8

tools/c-index-test/Makefile

@@ -19,6 +19,7 @@ TOOL_NO_EXPORTS = 1
 
 LINK_COMPONENTS := support mc
 USEDLIBS = clang.a clangFrontend.a clangDriver.a \
+	   clangTooling.a \
 	   clangSerialization.a clangParse.a clangSema.a \
 	   clangAnalysis.a clangEdit.a clangAST.a clangLex.a \
 	   clangBasic.a