message: use nightly build, per code review
diff: @@ -23,8 +23,8 @@ else
  $(error $n Can't detect OS properly. $n This will impede automatically downloading the correct stanc. $n Please visit https://github.com/stan-dev/stanc3/releases and download a stanc binary for your OS and place it in ./bin/stanc)
  endif
  +# bin/stanc build rules - requires stan, stan_math submodules in place
  ifeq ($(CMDSTAN_SUBMODULES),1)
  -# bin/stanc build rules
  ifneq ($(STANC2),)
  bin/stanc$(EXE) : O = $(O_STANC)
  bin/stanc$(EXE) : CPPFLAGS_MPI =
  @@ -49,11 +49,10 @@ bin/stanc$(EXE) :
  else ifeq ($(OS_TAG),windows)
  bin/stanc$(EXE) :
  @mkdir -p $(dir $@)
  -https://github.com/stan-dev/stan/releases/latest
  - $(shell echo "curl -L https://github.com/stan-dev/stanc3/releases/download/latest/$(OS_TAG)-stanc -o bin/stanc$(EXE)")
  + $(shell echo "curl -L https://github.com/stan-dev/stanc3/releases/download/nightly/$(OS_TAG)-stanc -o bin/stanc$(EXE)")
  else
  bin/stanc$(EXE) :
  - curl -L https://github.com/stan-dev/stanc3/releases/download/latest/$(OS_TAG)-stanc -o bin/stanc
  + curl -L https://github.com/stan-dev/stanc3/releases/download/nightly/$(OS_TAG)-stanc -o bin/stanc
  chmod +x bin/stanc
  endif
  @@ -75,7 +74,8 @@ $(patsubst %.cpp,%.d,$(STANC_TEMPLATE_INSTANTIATION_CPP)) : DEPTARGETS = -MT $(p
  ifneq ($(filter bin/stanc$(EXE) bin/stan/libstanc.a $(STANC_TEMPLATE_INSTANTIATION),$(MAKECMDGOALS)),)
  -include $(patsubst %.cpp,%.d,$(STANC_TEMPLATE_INSTANTIATION_CPP))
  endif
  +# end libstanc build rules
  -# end bin/stanc build rules
  endif
  +# end bin/stanc build rules
  