I am using Teensy 4.0, and need to include USBHost_t36.h
There is a problem adding USBHost_t36 lib. Get all sorts of lib compile issues when adding
#include “USBHost_t36.h” to a blank sketch.
Yet works just fine when using Arduino 1.8.19.
I followed the installation information here.
But the library in the registry says
Connect USB devices to the USB Host of Teensy 3.6.
So no compatiblility with 4.0 mentioned. That is however because the library was last updated in the registry 4 years ago and the library has recent improvements. So, you should try
lib_deps = https://github.com/PaulStoffregen/USBHost_t36/archive/refs/heads/master.zip
After my PR is merged, a new version is now available: PlatformIO Registry
Try using that directly.