Hi, I'm happy to go along with what you said, but I have a few comments. If we decide to read from an environment variable, we should read it from the existing @address@hidden It doesn't make sense to use $PATH since that has a different purpose on Linux systems (namely, searching for binaries).
Further, the reason I made it compile-time configurable is two-fold: consistency with existing code and to allow the maintainer to set a reasonable default. If we're doing this to make it more convenient for (potentially non-technical users), it's generally the maintainer's job to adapt the search path to their system. The user shouldn't have to manually edit the path themselves. Although, one approach is to have a global file like /etc/fluidsynth.rc (filled by the maintainer) and then make the local one (empty by default, filled by the user) take precedence.
Thanks for the feedback.