This case was detected when trying to build ulogd2 on a musl libc based
environment, because musl doesn't provide <sys/queue.h>.
according to a short discussion on #musl:
dalias> sys/queue.h has nothing to do with libc. it's a linked list/queue
implementation entirely in a header file
Do not use the FILE struct as marker to check if the user requested to use
syslog.
In musl the FILE struct is opaque, thus its storage size is not known to
the application.
This means that when using musl it has to be use as a pointer like it was
intended to be used.