Add some fixes to the configure script  for isInf and add
--enable-libcpp to projects/sample.

Patch by Dmitri Shubin with additional fixes by me.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153425 91177308-0d34-0410-b5e6-96231b3b80d8
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>],