diff --git a/projects/sample/autoconf/configure.ac b/projects/sample/autoconf/configure.ac
index a19e87d..1caff51 100644
--- a/projects/sample/autoconf/configure.ac
+++ b/projects/sample/autoconf/configure.ac
@@ -745,33 +745,15 @@
 AC_DEFINE_UNQUOTED(C_INCLUDE_DIRS,"$withval",
                    [Directories clang will search for headers])
 
-AC_ARG_WITH(cxx-include-root,
-  AS_HELP_STRING([--with-cxx-include-root],
-    [Directory with the libstdc++ headers.]),,
+# Clang normally uses the system c++ headers and libraries. With this option,
+# clang will use the ones provided by a gcc installation instead. This option should
+# be passed the same value that was used with --prefix when configuring gcc.
+AC_ARG_WITH(gcc-toolchain,
+  AS_HELP_STRING([--with-gcc-toolchain],
+    [Directory where gcc is installed.]),,
     withval="")
-AC_DEFINE_UNQUOTED(CXX_INCLUDE_ROOT,"$withval",
-                   [Directory with the libstdc++ headers.])
-
-AC_ARG_WITH(cxx-include-arch,
-  AS_HELP_STRING([--with-cxx-include-arch],
-    [Architecture of the libstdc++ headers.]),,
-    withval="")
-AC_DEFINE_UNQUOTED(CXX_INCLUDE_ARCH,"$withval",
-                   [Arch the libstdc++ headers.])
-
-AC_ARG_WITH(cxx-include-32bit-dir,
-  AS_HELP_STRING([--with-cxx-include-32bit-dir],
-    [32 bit multilib dir.]),,
-    withval="")
-AC_DEFINE_UNQUOTED(CXX_INCLUDE_32BIT_DIR,"$withval",
-                   [32 bit multilib directory.])
-
-AC_ARG_WITH(cxx-include-64bit-dir,
-  AS_HELP_STRING([--with-cxx-include-64bit-dir],
-    [64 bit multilib directory.]),,
-    withval="")
-AC_DEFINE_UNQUOTED(CXX_INCLUDE_64BIT_DIR,"$withval",
-                   [64 bit multilib directory.])
+AC_DEFINE_UNQUOTED(GCC_INSTALL_PREFIX,"$withval",
+                   [Directory where gcc is installed.])
 
 dnl Allow linking of LLVM with GPLv3 binutils code.
 AC_ARG_WITH(binutils-include,