gn build: Fix clang-tidy build

Not depending on //clang/lib/StaticAnalyzer/Core and
//clang/lib/StaticAnalyzer/Frontend causes a linker error even if
ClangSACheckers are not supported.

Undefined symbols for architecture x86_64:
  "clang::ento::CreateAnalysisConsumer(clang::CompilerInstance&)", referenced from:
      clang::tidy::ClangTidyASTConsumerFactory::CreateASTConsumer(
              clang::CompilerInstance&, llvm::StringRef)
          in libclangTidy.a(libclangTidy.ClangTidy.o)

Patch from Mirko Bonadei <mbonadei@webrtc.org>!

Differential Revision: https://reviews.llvm.org/D57777

llvm-svn: 353244

llvm/utils/gn/secondary/clang-tools-extra/clang-tidy/BUILD.gn

@@ -22,14 +22,12 @@ static_library("clang-tidy") {
     # ClangSACheckers
   ]
 
-  # TODO(mbonadei): Add support for Clang Static Analyzer checkers.
-  # Without this, "clang-analyzer-" will not work.
-  # if (clang_enable_static_analyzer) {
-  #   deps += [
-  #     "//clang/lib/StaticAnalyzer/Core",
-  #     "//clang/lib/StaticAnalyzer/Frontend",
-  #   ]
-  # }
+  if (clang_enable_static_analyzer) {
+    deps += [
+      "//clang/lib/StaticAnalyzer/Core",
+      "//clang/lib/StaticAnalyzer/Frontend",
+    ]
+  }
 
   sources = [
     "ClangTidy.cpp",