check target execution possibility

[Kamil Samigullin]

in some cases, I don't want to use tools/etc, but I use a template and it's not ok to adapt it locally.
it will be great to use check before enabling some targets:

ifeq (, wildcard(tools/*))
  target with stub
else
  valid target
endif

candidates:

• tools
• dist without goreleaser/godownloader
• git hooks