fixed point arithmetic

[umlaeute]

while packaging faust-2.74.6 for Debian, I tried to test the new faust2comparator with faust2comparator foo.dsp -fx-size 48 as described in https://github.com/grame-cncm/faust/blob/b498ef5159a0a02a98e92dd3d6998859fae2c8a8/architecture/comparator/README.md?plain=1#L9

however, this gives me build errors:

1. it cannot find float.cpp (which is generated in the cwd, so adding -I. to the compiler invocation fixes the problem)
2. however, float.cpp then goes on to include ap_fixed.h, which is supposed to live in /usr/local/include/ap_fixed/; at least if I read the compiler invocation correctly: https://github.com/grame-cncm/faust/blob/b498ef5159a0a02a98e92dd3d6998859fae2c8a8/tools/faust2appls/faust2comparator#L60

now, I do not have a /usr/local/include/ap_fixed/ap_fixed.h file (nor the entire directory).

where does it come from? probably something like https://github.com/Xilinx/HLS_arbitrary_Precision_Types.git, but using the Xilinx headers gives me template-errors (unfortunately i didn't write them down before deleting the container).

It would be nice if there were some hints on how to use the fixed-point backends (e.g. what to install where)