Alter test for std::put_time to work on clang+libstdc++

src/gettext_boost.cpp

@@ -436,7 +436,8 @@ std::string strftime(const std::string& format, const std::tm* time)
 {
 	std::basic_ostringstream<char> dummy;
 	dummy.imbue(get_manager().get_locale());
-#if defined(__GNUC__) && !defined(__clang__) && __GNUC__ < 5
+	// See utils/io.hpp for explanation of this check
+#if (defined(__clang__) && !__has_include(<experimental/any>) || (defined(__GNUC__) && __GNUC__ < 5)
 	dummy << bl::as::ftime(format) << mktime(const_cast<std::tm*>(time));
 #else
 	dummy << std::put_time(time, format.c_str());

src/utils/io.hpp

@@ -11,7 +11,13 @@ but WITHOUT ANY WARRANTY.
 See the COPYING file for more details.
 */
 
-#if defined(__GNUC__) && !defined(__clang__) && __GNUC__ < 5
+// The version of libstdc++ shipped with GCC 4.x does not have put_time in the <iomanip> header
+// Thus if GCC is the compiler being used, we can simply check the compiler version.
+// However, if clang is being used, this won't work.
+// Instead, we check for the presence of the <experimental/any> header.
+// This was introduced in GCC 5.1, so it's not a perfect check, but it appears to be the best available.
+// (Boost also uses the same check internally.)
+#if (defined(__clang__) && !__has_include(<experimental/any>) || (defined(__GNUC__) && __GNUC__ < 5)
 
 #include <ctime>