diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2087c6a8a710576e9096f523ea33e02eea1d998a..bb92fee75b46c6f89d29f58243915bc8d27c853e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -234,7 +234,7 @@ install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/include/
   PATTERN "*.inc"
   )
 
-add_definitions( -D_GNU_SOURCE -DHAVE_CLANG_CONFIG_H )
+add_definitions( -D_GNU_SOURCE )
 
 # Clang version information
 set(CLANG_EXECUTABLE_VERSION
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index 26ceb32e73ee4b80d1573c9841ef9bbdd0c9905a..b494ed12396ed677c89b9e3b3ab78507799dfb39 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -36,13 +36,10 @@
 #include "InputInfo.h"
 #include "ToolChains.h"
 
-#ifdef HAVE_CLANG_CONFIG_H
-# include "clang/Config/config.h"
-#endif
-#include "llvm/Config/config.h"
-
 #include <map>
 
+#include "clang/Config/config.h"
+
 using namespace clang::driver;
 using namespace clang;
 
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 8c7158f0bffae5d03f42ea698fbaa3cfe304688b..703c7aa3d52c68aec039d33fb492aea69f79ca69 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -33,11 +33,7 @@
 
 #include <cstdlib> // ::getenv
 
-#ifdef HAVE_CLANG_CONFIG_H
-# include "clang/Config/config.h"
-#endif
-
-#include "llvm/Config/config.h" // for GCC_INSTALL_PREFIX
+#include "clang/Config/config.h" // for GCC_INSTALL_PREFIX
 
 using namespace clang::driver;
 using namespace clang::driver::toolchains;
diff --git a/lib/Frontend/InitHeaderSearch.cpp b/lib/Frontend/InitHeaderSearch.cpp
index 67b2287604d1a6f771647cf90c79905f4688ec6b..ee4b4eb5cd30cf85bbaa19bebd85d315b9fc8bf6 100644
--- a/lib/Frontend/InitHeaderSearch.cpp
+++ b/lib/Frontend/InitHeaderSearch.cpp
@@ -26,11 +26,8 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Path.h"
 
-#ifdef HAVE_CLANG_CONFIG_H
-# include "clang/Config/config.h"
-#endif
+#include "clang/Config/config.h" // C_INCLUDE_DIRS
 
-#include "llvm/Config/config.h"
 using namespace clang;
 using namespace clang::frontend;