Make it possible for client code to consume CLANG_LINK_CLANG_DYLIB

If a client code wants to consume clang libraries, it needs to know
CLANG_LINK_CLANG_DYLIB value in order to decide whether to use the DYLIB or
individual components.

Differential Revision: https://reviews.llvm.org/D82291

clang/cmake/modules/ClangConfig.cmake.in

@@ -8,6 +8,7 @@ find_package(LLVM REQUIRED CONFIG
 set(CLANG_EXPORTED_TARGETS "@CLANG_EXPORTS@")
 set(CLANG_CMAKE_DIR "@CLANG_CONFIG_CMAKE_DIR@")
 set(CLANG_INCLUDE_DIRS "@CLANG_CONFIG_INCLUDE_DIRS@")
+set(CLANG_LINK_CLANG_DYLIB "@CLANG_LINK_CLANG_DYLIB@")
 
 # Provide all our library targets to users.
 include("@CLANG_CONFIG_EXPORTS_FILE@")