diff --git a/autoconf/m4/func_isinf.m4 b/autoconf/m4/func_isinf.m4
index c936bf9..5c000f8 100644
--- a/autoconf/m4/func_isinf.m4
+++ b/autoconf/m4/func_isinf.m4
@@ -19,7 +19,7 @@
 
 AC_SINGLE_CXX_CHECK([ac_cv_func_std_isinf_in_cmath],
                     [std::isinf], [<cmath>],
-                    [float f; std::isinf(f)}])
+                    [float f; std::isinf(f);])
 if test "$ac_cv_func_std_isinf_in_cmath" = "yes" ; then 
   AC_DEFINE([HAVE_STD_ISINF_IN_CMATH],1,[Set to 1 if the std::isinf function is found in <cmath>])
 fi
diff --git a/autoconf/m4/huge_val.m4 b/autoconf/m4/huge_val.m4
index 5fffbfc..7ef9dca 100644
--- a/autoconf/m4/huge_val.m4
+++ b/autoconf/m4/huge_val.m4
@@ -6,7 +6,7 @@
   AC_CACHE_CHECK([for HUGE_VAL sanity], [ac_cv_huge_val_sanity],[
     AC_LANG_PUSH([C++])
     ac_save_CXXFLAGS=$CXXFLAGS
-    CXXFLAGS=-pedantic
+    CXXFLAGS+=" -pedantic"
     AC_RUN_IFELSE(
       AC_LANG_PROGRAM(
         [#include <math.h>],
diff --git a/configure b/configure
index 941d54c..2dfd66d 100755
--- a/configure
+++ b/configure
@@ -16361,7 +16361,7 @@
 ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
     ac_save_CXXFLAGS=$CXXFLAGS
-    CXXFLAGS=-pedantic
+    CXXFLAGS+=" -pedantic"
     if test "$cross_compiling" = yes; then
   ac_cv_huge_val_sanity=yes
 else
@@ -19987,7 +19987,7 @@
 int
 main ()
 {
-float f; std::isinf(f)}
+float f; std::isinf(f);
   ;
   return 0;
 }
diff --git a/projects/sample/Makefile.llvm.config.in b/projects/sample/Makefile.llvm.config.in
index deef6b2..697660c 100644
--- a/projects/sample/Makefile.llvm.config.in
+++ b/projects/sample/Makefile.llvm.config.in
@@ -182,6 +182,10 @@
 # These are options that can either be enabled here, or can be enabled on the
 # make command line (ie, make ENABLE_PROFILING=1):
 
+# When ENABLE_LIBCPP is enabled, LLVM uses libc++ by default to build.
+#ENABLE_LIBCPP = 0
+ENABLE_LIBCPP = @ENABLE_LIBCPP@
+
 # When ENABLE_OPTIMIZED is enabled, LLVM code is optimized and output is put
 # into the "Release" directories. Otherwise, LLVM code is not optimized and
 # output is put in the "Debug" directories.
diff --git a/projects/sample/Makefile.llvm.rules b/projects/sample/Makefile.llvm.rules
index 7467d84..6e04724 100644
--- a/projects/sample/Makefile.llvm.rules
+++ b/projects/sample/Makefile.llvm.rules
@@ -245,6 +245,11 @@
   endif
 endif
 
+ifeq ($(ENABLE_LIBCPP),1)
+  CXX.Flags +=  -stdlib=libc++
+  LD.Flags +=  -stdlib=libc++
+endif
+
 ifeq ($(ENABLE_PROFILING),1)
   BuildMode := $(BuildMode)+Profile
   CXX.Flags := $(filter-out -fomit-frame-pointer,$(CXX.Flags)) -pg -g
diff --git a/projects/sample/autoconf/configure.ac b/projects/sample/autoconf/configure.ac
index d52574f..f7b58ed 100644
--- a/projects/sample/autoconf/configure.ac
+++ b/projects/sample/autoconf/configure.ac
@@ -360,6 +360,18 @@
 dnl===
 dnl===-----------------------------------------------------------------------===
 
+dnl --enable-libcpp : check whether or not to use libc++ on the command line
+AC_ARG_ENABLE(libcpp,
+              AS_HELP_STRING([--enable-libcpp],
+                             [Use libc++ if available (default is NO)]),,
+                             enableval=default)
+case "$enableval" in
+  yes) AC_SUBST(ENABLE_LIBCPP,[1]) ;;
+  no)  AC_SUBST(ENABLE_LIBCPP,[0]) ;;
+  default) AC_SUBST(ENABLE_LIBCPP,[0]);;
+  *) AC_MSG_ERROR([Invalid setting for --enable-libcpp. Use "yes" or "no"]) ;;
+esac
+
 dnl --enable-optimized : check whether they want to do an optimized build:
 AC_ARG_ENABLE(optimized, AS_HELP_STRING(
  --enable-optimized,[Compile with optimizations enabled (default is NO)]),,enableval=$optimize)
diff --git a/projects/sample/autoconf/m4/func_isinf.m4 b/projects/sample/autoconf/m4/func_isinf.m4
index c936bf9..5c000f8 100644
--- a/projects/sample/autoconf/m4/func_isinf.m4
+++ b/projects/sample/autoconf/m4/func_isinf.m4
@@ -19,7 +19,7 @@
 
 AC_SINGLE_CXX_CHECK([ac_cv_func_std_isinf_in_cmath],
                     [std::isinf], [<cmath>],
-                    [float f; std::isinf(f)}])
+                    [float f; std::isinf(f);])
 if test "$ac_cv_func_std_isinf_in_cmath" = "yes" ; then 
   AC_DEFINE([HAVE_STD_ISINF_IN_CMATH],1,[Set to 1 if the std::isinf function is found in <cmath>])
 fi
diff --git a/projects/sample/autoconf/m4/huge_val.m4 b/projects/sample/autoconf/m4/huge_val.m4
index 5fffbfc..7ef9dca 100644
--- a/projects/sample/autoconf/m4/huge_val.m4
+++ b/projects/sample/autoconf/m4/huge_val.m4
@@ -6,7 +6,7 @@
   AC_CACHE_CHECK([for HUGE_VAL sanity], [ac_cv_huge_val_sanity],[
     AC_LANG_PUSH([C++])
     ac_save_CXXFLAGS=$CXXFLAGS
-    CXXFLAGS=-pedantic
+    CXXFLAGS+=" -pedantic"
     AC_RUN_IFELSE(
       AC_LANG_PROGRAM(
         [#include <math.h>],
diff --git a/projects/sample/configure b/projects/sample/configure
index a362e63..539e27d 100755
--- a/projects/sample/configure
+++ b/projects/sample/configure
@@ -682,6 +682,7 @@
 BUILD_EXEEXT
 BUILD_CXX
 CVSBUILD
+ENABLE_LIBCPP
 ENABLE_OPTIMIZED
 ENABLE_PROFILING
 DISABLE_ASSERTIONS
@@ -1373,6 +1374,7 @@
   --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
   --enable-polly          Use polly if available (default is YES)
+  --enable-libcpp         Use libc++ if available (default is NO)
   --enable-optimized      Compile with optimizations enabled (default is NO)
   --enable-profiling      Compile with profiling enabled (default is NO)
   --enable-assertions     Compile with assertion checks enabled (default is
@@ -4913,6 +4915,25 @@
 fi
 
 
+# Check whether --enable-libcpp was given.
+if test "${enable_libcpp+set}" = set; then
+  enableval=$enable_libcpp;
+else
+  enableval=default
+fi
+
+case "$enableval" in
+  yes) ENABLE_LIBCPP=1
+ ;;
+  no)  ENABLE_LIBCPP=0
+ ;;
+  default) ENABLE_LIBCPP=0
+;;
+  *) { { echo "$as_me:$LINENO: error: Invalid setting for --enable-libcpp. Use \"yes\" or \"no\"" >&5
+echo "$as_me: error: Invalid setting for --enable-libcpp. Use \"yes\" or \"no\"" >&2;}
+   { (exit 1); exit 1; }; } ;;
+esac
+
 # Check whether --enable-optimized was given.
 if test "${enable_optimized+set}" = set; then
   enableval=$enable_optimized;
@@ -10269,7 +10290,7 @@
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 10272 "configure"
+#line 10293 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -15930,7 +15951,7 @@
 ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
     ac_save_CXXFLAGS=$CXXFLAGS
-    CXXFLAGS=-pedantic
+    CXXFLAGS+=" -pedantic"
     if test "$cross_compiling" = yes; then
   ac_cv_huge_val_sanity=yes
 else
@@ -19555,7 +19576,7 @@
 int
 main ()
 {
-float f; std::isinf(f)}
+float f; std::isinf(f);
   ;
   return 0;
 }
@@ -21601,6 +21622,7 @@
 BUILD_EXEEXT!$BUILD_EXEEXT$ac_delim
 BUILD_CXX!$BUILD_CXX$ac_delim
 CVSBUILD!$CVSBUILD$ac_delim
+ENABLE_LIBCPP!$ENABLE_LIBCPP$ac_delim
 ENABLE_OPTIMIZED!$ENABLE_OPTIMIZED$ac_delim
 ENABLE_PROFILING!$ENABLE_PROFILING$ac_delim
 DISABLE_ASSERTIONS!$DISABLE_ASSERTIONS$ac_delim
@@ -21615,7 +21637,6 @@
 ENABLE_THREADS!$ENABLE_THREADS$ac_delim
 ENABLE_PTHREADS!$ENABLE_PTHREADS$ac_delim
 ENABLE_PIC!$ENABLE_PIC$ac_delim
-ENABLE_SHARED!$ENABLE_SHARED$ac_delim
 _ACEOF
 
   if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 97; then
@@ -21657,6 +21678,7 @@
 ac_delim='%!_!# '
 for ac_last_try in false false false false false :; do
   cat >conf$$subs.sed <<_ACEOF
+ENABLE_SHARED!$ENABLE_SHARED$ac_delim
 ENABLE_EMBED_STDCXX!$ENABLE_EMBED_STDCXX$ac_delim
 ENABLE_TIMESTAMPS!$ENABLE_TIMESTAMPS$ac_delim
 TARGETS_TO_BUILD!$TARGETS_TO_BUILD$ac_delim
@@ -21747,7 +21769,7 @@
 LTLIBOBJS!$LTLIBOBJS$ac_delim
 _ACEOF
 
-  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 88; then
+  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 89; then
     break
   elif $ac_last_try; then
     { { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5