[CMake] Pass CLANG_VERSION_* variables into later stages

When supporting overriding clang versions we also need to pass those through to the next stage so they remain overridden.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@282109 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -549,6 +549,9 @@ if (CLANG_ENABLE_BOOTSTRAP)
     LLVM_VERSION_MAJOR
     LLVM_VERSION_MINOR
     LLVM_VERSION_PATCH
+    CLANG_VERSION_MAJOR
+    CLANG_VERSION_MINOR
+    CLANG_VERSION_PATCHLEVEL
     LLVM_VERSION_SUFFIX
     LLVM_BINUTILS_INCDIR
     CLANG_REPOSITORY_STRING