Require a version in a Makefile

Makefile

## Make version management ##

# For Mac users: ensure we aren't using the outdated 2004 3.81 release shipped with Macs
# or a particularly old GNU Make

MAKE_REQUIRED_MAJOR_VERSION := 4
MAKE_VERSION := $(shell $(MAKE) --version | head -1 | cut -d ' ' -f 3)
MAKE_MAJOR_VERSION := $(shell echo $(MAKE_VERSION) | cut -d '.' -f 1)
COMPARE_MAKE_VERSIONS := $(shell printf "$(MAKE_MAJOR_VERSION)\n$(MAKE_REQUIRED_MAJOR_VERSION)" | sort | head -1)

ifeq ($(MAKE_VERSION),3.81)
$(error Error: The Make version is 3.81. This is the 2004 version packaged with MacOS which is missing new features. Please install GNU make with brew.)
endif

# If not equal, this is because COMPARE_MAKE_VERSIONS < required version
ifneq ($(COMPARE_MAKE_VERSIONS),$(MAKE_REQUIRED_MAJOR_VERSION))
$(error Error: The Make version is below the suggested major version $(MAKE_REQUIRED_MAJOR_VERSION) and should be upgraded. On a Mac, install/update with brew.)
endif

## Targets ##

all: