Using Raspbian Stretch.
I installed gcc-4.9 with specified version. Then I installed arduino (18.104.22.168) which in turn pulled gcc 4.6. When I try to compile Marlin in it, it says
Marlin requires C++11 support (gcc >= 4.7, Arduino IDE >= 1.6.8). Please upgrade your toolchain.
How do I make Arduino IDE use the correct version of GCC?