CMake: add support for CLANG_VENDOR. PR9966.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131733 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 04e1654..aa89823 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -57,6 +57,13 @@
 set(C_INCLUDE_DIRS "" CACHE STRING
   "Colon separated list of directories clang will search for headers.")
 
+set(CLANG_VENDOR "" CACHE STRING
+  "Vendor-specific text for showing with version information.")
+
+if( CLANG_VENDOR )
+  add_definitions( -DCLANG_VENDOR="${CLANG_VENDOR} " )
+endif()
+
 set(CLANG_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(CLANG_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})