Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -199,6 +199,8 @@
 set(ENABLE_X86_RELAX_RELOCATIONS OFF CACHE BOOL
     "enable x86 relax relocations by default")
 
+option(CLANG_PREFER_GCC_LIBRARIES "Prefer libraries installed next to GCC." ON)
+
 set(CLANG_DEFAULT_LINKER "" CACHE STRING
   "Default linker to use (linker name or absolute path, empty for platform default)")
 
Index: include/clang/Config/config.h.cmake
===================================================================
--- include/clang/Config/config.h.cmake
+++ include/clang/Config/config.h.cmake
@@ -8,6 +8,9 @@
 /* Bug report URL. */
 #define BUG_REPORT_URL "${BUG_REPORT_URL}"
 
+/* Prefer libraries installed next to GCC. */
+#cmakedefine CLANG_PREFER_GCC_LIBRARIES
+
 /* Default linker to use. */
 #define CLANG_DEFAULT_LINKER "${CLANG_DEFAULT_LINKER}"
 
Index: lib/Driver/ToolChains.cpp
===================================================================
--- lib/Driver/ToolChains.cpp
+++ lib/Driver/ToolChains.cpp
@@ -12,7 +12,7 @@
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Version.h"
 #include "clang/Basic/VirtualFileSystem.h"
-#include "clang/Config/config.h" // for GCC_INSTALL_PREFIX
+#include "clang/Config/config.h" // for CLANG_PREFER_GCC_LIBRARIES and GCC_INSTALL_PREFIX
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Distro.h"
 #include "clang/Driver/Driver.h"
@@ -4161,6 +4161,19 @@
   const std::string OSLibDir = getOSLibDir(Triple, Args);
   const std::string MultiarchTriple = getMultiarchTriple(D, Triple, SysRoot);
 
+#ifndef CLANG_PREFER_GCC_LIBRARIES
+  // Similar to the logic for GCC below, if we currently running Clang inside
+  // of the requested system root, add its parent library paths to those
+  // searched.
+  // FIXME: It's not clear whether we should use the driver's installed
+  // directory ('Dir' below) or the ResourceDir.
+  if (StringRef(D.Dir).startswith(SysRoot)) {
+    addPathIfExists(D, D.Dir + "/../lib/" + MultiarchTriple, Paths);
+    addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
+    addPathIfExists(D, D.Dir + "/../lib", Paths);
+  }
+#endif
+
   // Add the multilib suffixed paths where they are available.
   if (GCCInstallation.isValid()) {
     const llvm::Triple &GCCTriple = GCCInstallation.getTriple();
@@ -4214,6 +4227,7 @@
     }
   }
 
+#ifdef CLANG_PREFER_GCC_LIBRARIES
   // Similar to the logic for GCC above, if we currently running Clang inside
   // of the requested system root, add its parent library paths to
   // those searched.
@@ -4223,6 +4237,7 @@
     addPathIfExists(D, D.Dir + "/../lib/" + MultiarchTriple, Paths);
     addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
   }
+#endif
 
   addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
   addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
@@ -4260,6 +4275,7 @@
       addPathIfExists(D, LibPath, Paths);
   }
 
+#ifdef CLANG_PREFER_GCC_LIBRARIES
   // Similar to the logic for GCC above, if we are currently running Clang
   // inside of the requested system root, add its parent library path to those
   // searched.
@@ -4267,6 +4283,7 @@
   // directory ('Dir' below) or the ResourceDir.
   if (StringRef(D.Dir).startswith(SysRoot))
     addPathIfExists(D, D.Dir + "/../lib", Paths);
+#endif
 
   addPathIfExists(D, SysRoot + "/lib", Paths);
   addPathIfExists(D, SysRoot + "/usr/lib", Paths);