Build: Move TF source file inclusion from build system to source files

Outside of compiler-rt (where it's arguably an anti-pattern too),
LLVM tries to keep its build files as simple as possible. See e.g.
llvm/docs/SupportLibrary.rst, "Code Organization".

Differential Revision: https://reviews.llvm.org/D84243
diff --git a/llvm/lib/Analysis/MLInlineAdvisor.cpp b/llvm/lib/Analysis/MLInlineAdvisor.cpp
index 45873f2..31cb43b 100644
--- a/llvm/lib/Analysis/MLInlineAdvisor.cpp
+++ b/llvm/lib/Analysis/MLInlineAdvisor.cpp
@@ -11,6 +11,9 @@
 // 'release' mode) or a runtime-loaded model (the 'development' case).
 //
 //===----------------------------------------------------------------------===//
+#include "llvm/Config/config.h"
+#if defined(LLVM_HAVE_TF_AOT) || defined(LLVM_HAVE_TF_API)
+
 #include <limits>
 #include <unordered_map>
 #include <unordered_set>
@@ -298,4 +301,5 @@
     reportContextForRemark(R);
     return R;
   });
-}
\ No newline at end of file
+}
+#endif // defined(LLVM_HAVE_TF_AOT) || defined(LLVM_HAVE_TF_API)