Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -267,6 +267,13 @@
   add_definitions(-DCLANG_REPOSITORY_STRING="${CLANG_REPOSITORY_STRING}")
 endif()
 
+set(LLVM_REPOSITORY_STRING "" CACHE STRING
+  "Vendor-specific text for showing the repository the LLVM source is taken from.")
+
+if(LLVM_REPOSITORY_STRING)
+  add_definitions(-DLLVM_REPOSITORY_STRING="${LLVM_REPOSITORY_STRING}")
+endif()
+
 set(CLANG_VENDOR_UTI "org.llvm.clang" CACHE STRING
   "Vendor-specific uti.")
 
Index: lib/Basic/Version.cpp
===================================================================
--- lib/Basic/Version.cpp
+++ lib/Basic/Version.cpp
@@ -55,6 +55,9 @@
 }
 
 std::string getLLVMRepositoryPath() {
+#if defined(LLVM_REPOSITORY_STRING)
+  return LLVM_REPOSITORY_STRING;
+#else
 #ifdef LLVM_REPOSITORY
   StringRef URL(LLVM_REPOSITORY);
 #else
@@ -69,6 +72,7 @@
     URL = URL.substr(Start);
 
   return URL;
+#endif
 }
 
 std::string getClangRevision() {