Use std::for_each_n on supported versions, fall back to normal for lo…

…op otherwise

plugins/GigPlayer/GigPlayer.cpp

@@ -441,10 +441,18 @@ void GigInstrument::play( sampleFrame * _working_buffer )
 			// resampling, the ADSR doesn't get messed up
 			ADSR copy = sample.adsr;
 			const auto amplitude = copy.value();
+#if ((_MSC_VER >= 1914) || (__GNUC__ >= 9 && __GNUC_MINOR__ >= 3) || (__clang__ && __clang_major__ >= 5))
 			std::for_each_n(sampleData.begin(), samples, [&](auto& frame) {
 				frame[0] *= amplitude;
 				frame[1] *= amplitude;
 			});
+#else
+			// TODO: Ubuntu 20.04 CI change should be enough to remove this if/else
+			for (f_cnt_t i = 0; i < samples; ++i) {
+				sampleData[i][0] *= amplitude;
+				sampleData[i][1] *= amplitude;
+			}
+#endif
 
 			// Output the data resampling if needed
 			// Only output if resampling is successful (note that "used" is output)