Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/lib64/cmake/llvm/VersionFromVCS.cmake b/linux-x64/clang/lib64/cmake/llvm/VersionFromVCS.cmake
new file mode 100644
index 0000000..552fe77
--- /dev/null
+++ b/linux-x64/clang/lib64/cmake/llvm/VersionFromVCS.cmake
@@ -0,0 +1,92 @@
+# Adds version control information to the variable VERS. For
+# determining the Version Control System used (if any) it inspects the
+# existence of certain subdirectories under SOURCE_DIR (if provided as an
+# extra argument, otherwise uses CMAKE_CURRENT_SOURCE_DIR).
+
+function(add_version_info_from_vcs VERS)
+  SET(SOURCE_DIR ${ARGV1})
+  if("${SOURCE_DIR}" STREQUAL "")
+      SET(SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+  endif()
+  string(REPLACE "svn" "" result "${${VERS}}")
+  if( EXISTS "${SOURCE_DIR}/.svn" )
+    set(result "${result}svn")
+    # FindSubversion does not work with symlinks. See PR 8437
+    if( NOT IS_SYMLINK "${SOURCE_DIR}" )
+      find_package(Subversion)
+    endif()
+    if( Subversion_FOUND )
+      subversion_wc_info( ${SOURCE_DIR} Project )
+      if( Project_WC_REVISION )
+        set(SVN_REVISION ${Project_WC_REVISION} PARENT_SCOPE)
+        set(result "${result}-r${Project_WC_REVISION}")
+      endif()
+      if( Project_WC_URL )
+        set(LLVM_REPOSITORY ${Project_WC_URL} PARENT_SCOPE)
+      endif()
+    endif()
+  else()
+    find_program(git_executable NAMES git git.exe git.cmd)
+
+    if( git_executable )
+      # Run from a subdirectory to force git to print an absoute path.
+      execute_process(COMMAND ${git_executable} rev-parse --git-dir
+        WORKING_DIRECTORY ${SOURCE_DIR}/cmake
+        RESULT_VARIABLE git_result
+        OUTPUT_VARIABLE git_dir
+        ERROR_QUIET)
+      if(git_result EQUAL 0)
+        # Try to get a ref-id
+        string(STRIP "${git_dir}" git_dir)
+        set(result "${result}git")
+        if( EXISTS ${git_dir}/svn )
+          # Get the repository URL
+          execute_process(COMMAND
+            ${git_executable} svn info
+            WORKING_DIRECTORY ${SOURCE_DIR}
+            TIMEOUT 5
+            RESULT_VARIABLE git_result
+            OUTPUT_VARIABLE git_output
+            ERROR_QUIET)
+          if( git_result EQUAL 0 )
+            string(REGEX MATCH "URL: ([^ \n]*)" svn_url ${git_output})
+            if(svn_url)
+              set(LLVM_REPOSITORY ${CMAKE_MATCH_1} PARENT_SCOPE)
+            endif()
+          endif()
+
+          # Get the svn revision number for this git commit if one exists.
+          execute_process(COMMAND ${git_executable} svn find-rev HEAD
+            WORKING_DIRECTORY ${SOURCE_DIR}
+            TIMEOUT 5
+            RESULT_VARIABLE git_result
+            OUTPUT_VARIABLE git_head_svn_rev_number
+            OUTPUT_STRIP_TRAILING_WHITESPACE)
+          if( git_result EQUAL 0 AND git_output)
+            set(SVN_REVISION ${git_head_svn_rev_number} PARENT_SCOPE)
+            set(git_svn_rev "-svn-${git_head_svn_rev_number}")
+          else()
+            set(git_svn_rev "")
+          endif()
+        endif()
+
+        # Get the git ref id
+        execute_process(COMMAND
+          ${git_executable} rev-parse --short HEAD
+          WORKING_DIRECTORY ${SOURCE_DIR}
+          TIMEOUT 5
+          RESULT_VARIABLE git_result
+          OUTPUT_VARIABLE git_ref_id
+          OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+        if( git_result EQUAL 0 )
+          set(GIT_COMMIT ${git_ref_id} PARENT_SCOPE)
+          set(result "${result}${git_svn_rev}-${git_ref_id}")
+        else()
+          set(result "${result}${git_svn_rev}")
+        endif()
+      endif()
+    endif()
+  endif()
+  set(${VERS} ${result} PARENT_SCOPE)
+endfunction(add_version_info_from_vcs)