[clang-tools-extra] Fix linking dylib for LLVMFrontendOpenMP

Use LLVM_LINK_COMPONENTS to link the FrontendOpenMP library
instead of passing it explicitly to LINK_LIBS.  This fixes duplicating
the library when clang-tidy is linked to LLVM dylib.

Differential Revision: https://reviews.llvm.org/D71674

clang-tools-extra/clang-tidy/openmp/CMakeLists.txt

@@ -1,4 +1,6 @@
-set(LLVM_LINK_COMPONENTS support)
+set(LLVM_LINK_COMPONENTS
+  FrontendOpenMP
+  Support)
 
 add_clang_library(clangTidyOpenMPModule
   ExceptionEscapeCheck.cpp
@@ -11,5 +13,4 @@ add_clang_library(clangTidyOpenMPModule
   clangBasic
   clangTidy
   clangTidyUtils
-  LLVMFrontendOpenMP
   )