How can I write a makefile to auto-detect and parallelize the build with GNU Make?

Question

Not sure if this is possible in one Makefile alone, but I was hoping to write a Makefile in a way such that trying to build any target in the file auto-magically detects the num

Answer 1

Here's what I went with:

ifeq ($(OS),Linux)
        NUMPROC := $(shell grep -c ^processor /proc/cpuinfo)
else ifeq ($(OS),Darwin)
        NUMPROC := $(shell sysctl hw.ncpu | awk '{print $$2}')
endif

# Only take half as many processors as available
NUMPROC := $(shell echo "$(NUMPROC)/2"|bc)

ifeq ($(NUMPROC),0)
        NUMPROC = 1
endif