Index: contrib/llvm/tools/clang/lib/Driver/ToolChains.cpp
===================================================================
--- contrib/llvm/tools/clang/lib/Driver/ToolChains.cpp	(revision 255294)
+++ contrib/llvm/tools/clang/lib/Driver/ToolChains.cpp	(working copy)
@@ -1851,6 +1851,38 @@
   }
 }
 
+ToolChain::CXXStdlibType
+FreeBSD::GetCXXStdlibType(const ArgList &Args) const {
+  if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
+    StringRef Value = A->getValue();
+    if (Value == "libc++")
+      return ToolChain::CST_Libcxx;
+    if (Value == "libstdc++")
+      return ToolChain::CST_Libstdcxx;
+    getDriver().Diag(diag::err_drv_invalid_stdlib_name)
+      << A->getAsString(Args);
+  }
+
+  return getTriple().getOSMajorVersion() >= 10 ? ToolChain::CST_Libcxx :
+         ToolChain::CST_Libstdcxx;
+}
+
+void FreeBSD::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                          ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
+      DriverArgs.hasArg(options::OPT_nostdincxx))
+    return;
+
+  if (GetCXXStdlibType(DriverArgs) == ToolChain::CST_Libcxx)
+    addSystemInclude(DriverArgs, CC1Args,
+                     getDriver().SysRoot + "/usr/include/c++/v1");
+  else
+    addSystemInclude(DriverArgs, CC1Args,
+                     getDriver().SysRoot + "/usr/include/c++/4.2");
+  return;
+
+}
+
 /// NetBSD - NetBSD tool chain which can call as(1) and ld(1) directly.
 
 NetBSD::NetBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
Index: contrib/llvm/tools/clang/lib/Driver/ToolChains.h
===================================================================
--- contrib/llvm/tools/clang/lib/Driver/ToolChains.h	(revision 255294)
+++ contrib/llvm/tools/clang/lib/Driver/ToolChains.h	(working copy)
@@ -458,9 +458,14 @@
 public:
   FreeBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
 
+  virtual CXXStdlibType GetCXXStdlibType(const ArgList &Args) const;
+
   virtual bool IsMathErrnoDefault() const { return false; }
   virtual bool IsObjCNonFragileABIDefault() const { return true; }
 
+  virtual void AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                            ArgStringList &CC1Args) const;
+
   virtual bool UseSjLjExceptions() const;
 protected:
   virtual Tool *buildAssembler() const;
Index: gnu/lib/Makefile
===================================================================
--- gnu/lib/Makefile	(revision 255294)
+++ gnu/lib/Makefile	(working copy)
@@ -10,7 +10,7 @@
 
 # libsupc++ uses libstdc++ headers, although 'make includes' should
 # have taken care of that already.
-.if ${MK_CXX} != "no"
+.if ${MK_GNUCXX} != "no"
 SUBDIR+= libstdc++ libsupc++
 .endif
 
Index: gnu/usr.bin/cc/Makefile
===================================================================
--- gnu/usr.bin/cc/Makefile	(revision 255294)
+++ gnu/usr.bin/cc/Makefile	(working copy)
@@ -12,8 +12,13 @@
 .endif
 
 .if ${MK_CXX} != "no"
-SUBDIR+= cc1plus c++ c++filt
+.if ${MK_GNUCXX} != "no"
+SUBDIR+= cc1plus c++ 
 .endif
+# This should be moved into the above block once c++filt from elftoolchain or
+# similar is provided.
+SUBDIR+= c++filt
+.endif
 
 .if ${MK_GCOV} != "no"
 SUBDIR+= gcov
Index: share/mk/bsd.own.mk
===================================================================
--- share/mk/bsd.own.mk	(revision 255294)
+++ share/mk/bsd.own.mk	(working copy)
@@ -284,7 +284,6 @@
     FP_LIBC \
     FREEBSD_UPDATE \
     GAMES \
-    GCC \
     GCOV \
     GDB \
     GNU \
@@ -400,6 +399,11 @@
 .else
 __T=${MACHINE_ARCH}
 .endif
+.if defined(TARGET)
+__TT=${TARGET}
+.else
+__TT=${MACHINE_ARCH}
+.endif
 # Clang is only for x86, powerpc and little-endian arm right now, by default.
 .if ${__T} == "amd64" || ${__T} == "i386" || ${__T:Mpowerpc*}
 __DEFAULT_YES_OPTIONS+=CLANG CLANG_FULL
@@ -414,9 +418,31 @@
 .if ${__T} == "amd64" || ${__T} == "arm" || ${__T} == "armv6" || \
     ${__T} == "i386"
 __DEFAULT_YES_OPTIONS+=CLANG_IS_CC
+# The pc98 bootloader requires gcc to build and so we must leave gcc enabled
+# for pc98 for now.
+.if ${__TT} == "pc98"
+__DEFAULT_NO_OPTIONS+=GNUCXX
+__DEFAULT_YES_OPTIONS+=GCC
 .else
+__DEFAULT_NO_OPTIONS+=GCC GNUCXX
+.endif
+# The libc++ headers use c++11 extensions.  These are normally silenced because
+# they are treated as system headers, but we explicitly disable that warning
+# suppression when building the base system to catch bugs in our headers.
+# Eventually we'll want to start building the base system C++ code as C++11,
+# but not yet.
+CXXFLAGS+=	-Wno-c++11-extensions
+.else
+# If clang is not cc, then build gcc by default
 __DEFAULT_NO_OPTIONS+=CLANG_IS_CC
+__DEFAULT_YES_OPTIONS+=GCC
+# And if g++ is c++, build the rest of the GNU C++ stack
+.if defined(WITHOUT_CXX)
+__DEFAULT_NO_OPTIONS+=GNUCXX
+.else
+__DEFAULT_YES_OPTIONS+=GNUCXX
 .endif
+.endif
 # FDT is needed only for arm, mips and powerpc
 .if ${__T:Marm*} || ${__T:Mpowerpc*} || ${__T:Mmips*}
 __DEFAULT_YES_OPTIONS+=FDT
Index: sys/sys/param.h
===================================================================
--- sys/sys/param.h	(revision 255294)
+++ sys/sys/param.h	(working copy)
@@ -58,7 +58,7 @@
  *		in the range 5 to 9.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1000052	/* Master, propagated to newvers */
+#define __FreeBSD_version 1000053	/* Master, propagated to newvers */
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
Index: tools/build/options/WITHOUT_GNUCXX
===================================================================
--- tools/build/options/WITHOUT_GNUCXX	(revision 0)
+++ tools/build/options/WITHOUT_GNUCXX	(working copy)
@@ -0,0 +1,3 @@
+.\" $FreeBSD$
+Do not build the GNU C++ stack (g++, libstdc++).
+This is the default on platforms where clang is the system compiler.
Index: tools/build/options/WITH_GNUCXX
===================================================================
--- tools/build/options/WITH_GNUCXX	(revision 0)
+++ tools/build/options/WITH_GNUCXX	(working copy)
@@ -0,0 +1,3 @@
+.\" $FreeBSD$
+Build the GNU C++ stack (g++, libstdc++).
+This is the default on platforms where gcc is the system compiler.