From d198ccac2619b43671d39beac126342ea6d9cc64 Mon Sep 17 00:00:00 2001
From: Johannes Schickel
Date: Wed, 9 Jan 2013 07:53:21 +0100
Subject: CONFIGURE: Add option to build as C++11.

---
 configure | 50 +++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 41 insertions(+), 9 deletions(-)

diff --git a/configure b/configure
index b703776f8b..91364eb304 100755
--- a/configure
+++ b/configure
@@ -123,6 +123,7 @@ _libunity=auto
 _debug_build=auto
 _release_build=auto
 _optimizations=auto
+_use_cxx11=no
 _verbose_build=no
 _text_console=no
 _mt32emu=yes
@@ -870,6 +871,7 @@ Game engines:
     The values of <engine name> for these options are as follows:
 $engines_help
 Optional Features:
+  --enable-c++11           build as C++11 if the compiler allows that
   --disable-debug          disable building with debugging symbols
   --enable-Werror          treat warnings as errors
   --enable-release         enable building in release mode (this activates
@@ -1109,6 +1111,12 @@ for ac_option in $@; do
 	--backend=*)
 		_backend=`echo $ac_option | cut -d '=' -f 2`
 		;;
+	--enable-c++11)
+		_use_cxx11=yes
+		;;
+	--disable-c++11)
+		_use_cxx11=no
+		;;
 	--enable-debug)
 		_debug_build=yes
 		;;
@@ -1694,6 +1702,18 @@ if test "$cxx_verc_fail" = yes ; then
 	exit 1
 fi
 
+#
+# Check whether the compiler supports C++11
+#
+have_cxx11=no
+cat > $TMPC << EOF
+int main(int argc, char *argv[]) { if (argv == nullptr) return -1; else return 0; }
+EOF
+cc_check -std=c++11 && have_cxx11=yes
+if test "$_use_cxx11" = "yes" ; then
+	_use_cxx11=$have_cxx11
+fi
+
 #
 # Setup compiler specific CXXFLAGS now that we know the compiler version.
 # Foremost, this means enabling various warnings.
@@ -1701,15 +1721,18 @@ fi
 #
 if test "$have_gcc" = yes ; then
 	if test "$_cxx_major" -ge "3" ; then
-		case $_host_os in
-		# newlib-based system include files suppress non-C89 function
-		# declarations under __STRICT_ANSI__
-		amigaos* | android | bada | dreamcast | ds | gamecube | mingw* | n64 | psp | ps2 | ps3 | wii | wince )
-			;;
-		*)
-			CXXFLAGS="$CXXFLAGS -ansi"
-			;;
-		esac
+		# Try to use ANSI mode when C++11 is disabled.
+		if test "$_use_cxx11" = "no" ; then
+			case $_host_os in
+			# newlib-based system include files suppress non-C89 function
+			# declarations under __STRICT_ANSI__
+			amigaos* | android | bada | dreamcast | ds | gamecube | mingw* | n64 | psp | ps2 | ps3 | wii | wince )
+				;;
+			*)
+				CXXFLAGS="$CXXFLAGS -ansi"
+				;;
+			esac
+		fi
 		CXXFLAGS="$CXXFLAGS -W -Wno-unused-parameter"
 		add_line_to_config_mk 'HAVE_GCC3 = 1'
 		add_line_to_config_mk 'CXX_UPDATE_DEP_FLAG = -MMD -MF "$(*D)/$(DEPDIR)/$(*F).d" -MQ "$@" -MP'
@@ -1725,6 +1748,15 @@ elif test "$have_icc" = yes ; then
 	add_line_to_config_mk 'CXX_UPDATE_DEP_FLAG = -MMD -MF "$(*D)/$(DEPDIR)/$(*F).d" -MQ "$@" -MP'
 fi;
 
+#
+# Update status about C++11 mode
+#
+echo_n "Building as C++11... "
+if test "$_use_cxx11" = "yes" ; then
+	CXXFLAGS="$CXXFLAGS -std=c++11"
+fi
+echo $_use_cxx11
+
 # By default, we add -pedantic to the CXXFLAGS to catch some potentially
 # non-portable constructs, like use of GNU extensions.
 # However, some platforms use GNU extensions in system header files, so
-- 
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