Require C++11 support.

Set minimum compiler versions to:
GCC 4.7
clang 3.3
ICC 14.0

config.lib

@@ -1265,7 +1265,12 @@ make_compiler_cflags() {
 			# remark #2259: non-pointer conversion from ... to ... may lose significant bits
 			flags="$flags -wd2259"
 			# Use c++0x mode so static_assert() is available
-			cxxflags="$cxxflags -std=c++0x"
+			cxxflags="$cxxflags -std=c++11"
+		fi
+
+		if [ $cc_version -lt 140 ]; then
+			log 1 "configure: error: ICC version is too old: `$1 -dumpversion`, minumum: 14.0"
+			exit 1
 		fi
 
 		if [ "$enable_lto" != "0" ]; then
@@ -1329,6 +1334,9 @@ make_compiler_cflags() {
 		if [ "$cc_version" -ge "33" ]; then
 			# clang completed C++11 support in version 3.3
 			flags="$flags -std=c++11"
+		else
+			log 1 "configure: error: clang version is too old: `$1 -v 2>&1 | head -n 1`, minumum: 3.3"
+			exit 1
 		fi
 
 		# rdynamic is used to get useful stack traces from crash reports.
@@ -1390,7 +1398,7 @@ make_compiler_cflags() {
 		if [ $cc_version -ge 403 ] && [ $cc_version -lt 600 ]; then
 			# Use gnu++0x mode so static_assert() is available.
 			# Don't use c++0x, it breaks mingw (with gcc 4.4.0).
-			cxxflags="$cxxflags -std=gnu++0x"
+			cxxflags="$cxxflags -std=gnu++11"
 		fi
 
 		if [ $cc_version -eq 405 ]; then
@@ -1406,6 +1414,9 @@ make_compiler_cflags() {
 			cxxflags="$cxxflags -Wno-narrowing"
 			# Disable bogus 'attempt to free a non-heap object' warning
 			flags="$flags -Wno-free-nonheap-object"
+		else
+			log 1 "configure: error: GCC version is too old: `$1 -dumpversion`, minumum: 4.7"
+			exit 1
 		fi
 
 		if [ $cc_version -ge 600 ]; then