AudioPluginHost doesn't compile on Ubuntu 16.04

What is the oldest version of Linux that juce officially supports?

gcc (Ubuntu 5.5.0-12ubuntu1~16.04) 5.5.0 20171010
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Compiling PluginGraph.cpp
In file included from ../../Source/Plugins/InternalPlugins.cpp:41:0:
../../Source/Plugins/../../../../examples/Plugins/SamplerPluginDemo.h: In member function ‘std::tuple<double, MPESamplerVoice::Direction> MPESamplerVoice::getNextState(double, double, double) const’:
../../Source/Plugins/../../../../examples/Plugins/SamplerPluginDemo.h:466:51: error: converting to ‘std::tuple<double, MPESamplerVoice::Direction>’ from initializer list would use explicit constructor ‘constexpr std::tuple<_T1, _T2>::tuple(_U1&&, _U2&&) [with _U1 = double&; _U2 = MPESamplerVoice::Direction&; <template-parameter-2-3> = void; _T1 = double; _T2 = MPESamplerVoice::Direction]’
             return { nextSamplePos, nextDirection };
                                                   ^
../../Source/Plugins/../../../../examples/Plugins/SamplerPluginDemo.h:470:51: error: converting to ‘std::tuple<double, MPESamplerVoice::Direction>’ from initializer list would use explicit constructor ‘constexpr std::tuple<_T1, _T2>::tuple(_U1&&, _U2&&) [with _U1 = double&; _U2 = MPESamplerVoice::Direction&; <template-parameter-2-3> = void; _T1 = double; _T2 = MPESamplerVoice::Direction]’
             return { nextSamplePos, nextDirection };
                                                   ^
../../Source/Plugins/../../../../examples/Plugins/SamplerPluginDemo.h:482:47: error: converting to ‘std::tuple<double, MPESamplerVoice::Direction>’ from initializer list would use explicit constructor ‘constexpr std::tuple<_T1, _T2>::tuple(_U1&&, _U2&&) [with _U1 = double&; _U2 = MPESamplerVoice::Direction&; <template-parameter-2-3> = void; _T1 = double; _T2 = MPESamplerVoice::Direction]’
         return { nextSamplePos, nextDirection };
                                               ^
Makefile:108: recipe for target 'build/intermediate/Release/InternalPlugins_8278e3f5.o' failed

We support back to GCC 4.8, but this wasn’t being caught by our CI. We’ve updated the CI to do some more builds that should catch issues like this in the future, and added a workaround here: