message: Pull correct linux arch for stanc3
diff: @@ -22,6 +22,22 @@ else ifeq ($(OS),Darwin)
  STANC_XATTR := $(shell xattr bin/mac-stanc 2>/dev/null)
  else ifeq ($(OS),Linux)
  OS_TAG := linux
  + ifeq ($(shell uname -m),mips64)
  + ARCH_TAG := -mips64el
  + else ifeq ($(shell uname -m),ppc64le)
  + ARCH_TAG := -ppc64el
  + else ifeq ($(shell uname -m),s390x)
  + ARCH_TAG := -s390x
  + else ifeq ($(shell uname -m),aarch64)
  + ARCH_TAG := -arm64
  + else ifeq ($(shell uname -m),armv7l)
  + ifeq ($(readelf -A /proc/self/exe | grep Tag_ABI_VFP_args),)
  + ARCH_TAG := -armel
  + else
  + ARCH_TAG := -armhf
  + endif
  + endif
  +
  else ifeq ($(OS),missing-submodules)
  CMDSTAN_SUBMODULES = 0
  else
  @@ -45,7 +61,7 @@ ifeq ($(OS_TAG),windows)
  else
  bin/stanc$(EXE) :
  @mkdir -p $(dir $@)
  - curl -L $(STANC3_TEST_BIN_URL)/bin/$(OS_TAG)-stanc -o bin/stanc$(EXE) --retry $(STANC_DL_RETRY) --retry-delay $(STANC_DL_DELAY)
  + curl -L $(STANC3_TEST_BIN_URL)/bin/$(OS_TAG)$(ARCH_TAG)-stanc -o bin/stanc$(EXE) --retry $(STANC_DL_RETRY) --retry-delay $(STANC_DL_DELAY)
  chmod +x bin/stanc$(EXE)
  endif
  @@ -72,7 +88,7 @@ else
  # get latest stanc3 - Linux & MacOS
  bin/stanc$(EXE) :
  @mkdir -p $(dir $@)
  - curl -L https://github.com/stan-dev/stanc3/releases/download/$(STANC3_VERSION)/$(OS_TAG)-stanc -o bin/stanc$(EXE) --retry $(STANC_DL_RETRY) --retry-delay $(STANC_DL_DELAY)
  + curl -L https://github.com/stan-dev/stanc3/releases/download/$(STANC3_VERSION)/$(OS_TAG)$(ARCH_TAG)-stanc -o bin/stanc$(EXE) --retry $(STANC_DL_RETRY) --retry-delay $(STANC_DL_DELAY)
  chmod +x bin/stanc$(EXE)
  endif
  endif
  