Obtaining source .c for Pixhawk PSP library block

Just a follow up on this question: https://www.mathworks.com/matlabcentral/answers/331663-how-to-compile-tlc-to-mexw64-or-obtain-source-c-file

Apparently, the only way I can make an adjustment to the disarmed output of the PWM_output block (from the Pixhawk PSP for R2016a) is by editing the source .c file for that block and compiling it myself.

Where can I get a copy of this file (sfun_px4_pwm.c)? I need to make this change to avoid frying my servos.