[CMake][Modules] libclang: Ignore _CINDEX_LIB_ and CLANG_TOOL_EXTRA_BUILD for -fmodules.
[CMake][Modules] libclang: Ignore _CINDEX_LIB_ and CLANG_TOOL_EXTRA_BUILD for -fmodules.

CLANG_TOOL_EXTRA_BUILD doesn't affect headers.

_CINDEX_LIB_ is defined when the target is SHARED.
On Win32, it affects clang-c/Platform.h and it shouldn't be ignored.

This is part of https://reviews.llvm.org/D35559

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@309557 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang