Obviously the simplest thing is to try it...
But may assumption is that I believe the only place in the cores project that includes this file is the teensy3\avr_emulation.cpp.
So to use it, you need to include it.
But as Paul mentioned it only works on those 3 boards,
Also I believe it is limited to only work on the one SPI object. So for example on T3.5/6 with SPI1 and SPI2 there is no code in place to allow those to work. And it won't simply work by replacing which SPI object to use in the code as for example the FIFO queue sizes are different.
Note: for a long time, I setup my own library SPIN, which tried to add in the support for FIFO queues and different SPI ports and had versions that ran on different processors... I did this as part of T3.6 beta cycle. And for a long time, my ili9341_t3n library relied on this... But decided to remove the requirement for this, so a lot of support stuff is now replicated in each of the libraries that try to do this stuff...