I have used this in one of my projects, but in the end had to abandon it: the problem is that Guile itself requires GNU make during build, which creates a circular dependency, and thus building it with e.g. FreeBSD ports required manual intervention every time you updated it. This combined with the fact that this integration is only available since GNU make 4.0, and some Linux distributions still have older make, made it a hassle to setup. This should improve over time, of course.
Still a great feature though. Without it there are e.g. manipulations on the file paths that you can not do at all, or can do but only as a hack. Case in point: "GNU Make Standard Library" (https://gmsl.sourceforge.io/) is a collections of such hacks; here's its definition of 'strlen':
strlen = $(call assert_no_dollar,$0,$1)$(strip $(eval __temp := $(subst $(__gmsl_space),x,$1))$(foreach a,$(__gmsl_characters),$(eval __temp := $$(subst $$a,x,$(__temp))))$(eval __temp := $(subst x,x ,$(__temp)))$(words $(__temp)))
Still a great feature though. Without it there are e.g. manipulations on the file paths that you can not do at all, or can do but only as a hack. Case in point: "GNU Make Standard Library" (https://gmsl.sourceforge.io/) is a collections of such hacks; here's its definition of 'strlen':