This is libdrm, a userspace library for accessing the DRM, direct rendering manager, on Linux, BSD and other operating systems that support the ioctl interface. The library provides wrapper functions for the ioctls to avoid exposing the kernel interface directly, and for chipsets with drm memory manager, support for tracking relocations and buffers. New functionality in the kernel DRM drivers typically requires a new libdrm, but a new libdrm will always work with an older kernel.
libdrm is a low-level library, typically used by graphics drivers such as the Mesa drivers, the X drivers, libva and similar projects.
The library should be regularly updated to match the recent changes in the include/uapi/drm/.
libdrm maintains a human-readable version for the token format modifier, with the simpler ones being extracted automatically from drm_fourcc.h header file with the help of a python script. This might not always possible, as some of the vendors require decoding/extracting them programmatically. For that reason one can enhance the current vendor functions to include/provide the newly added token formats, or, in case there's no such decoding function, to add one that performs the tasks of extracting them.
For simpler format modifier tokens there's a script (gen_table_fourcc.py) that creates a static table, by going over drm_fourcc.h header file. The script could be further modified if it can't handle new (simpler) token format modifiers instead of the generated static table.
To set up meson:
meson builddir/
By default this will install into /usr/local, you can change your prefix with --prefix=/usr (or meson configure builddir/ -Dprefix=/usr after the initial meson setup).
Then use ninja to build and install:
ninja -C builddir/ install
If you are installing into a system location you will need to run install separately, and as root.