Docker Makefile calls nproc which does not work on Windows

[stephanegigandet]

In Makefile, we have:

OS := $(shell uname)

[..]
ifeq ($(OS), Darwin)
  export CPU_COUNT=$(shell sysctl -n hw.logicalcpu || echo 1)
else
  export CPU_COUNT=$(shell nproc || echo 1)
endif

This fails on Windows because nproc is not available.

Instead we could use %NUMBER_OF_PROCESSORS% (it's unclear if those are physical or logical cores)

I'm not sure what's the returned value of uname is on Windows though, could someone test and add a condition on it so that we call this on Windows?

$(shell echo %NUMBER_OF_PROCESSORS%)

[hangy]

Unfortunately, there's a bunch of *NIX related stuff in the Makefile, which makes it a bit annoying to work with this repo in a native Windows environment. That's one of the reasons why I mainly use WSL2 to develop ProdutctOpener now.

If you use the bash that's distributed with Git for Windows, this is the output, but then you have to use bash:

$ uname
MINGW64_NT-10.0-22000

$ nproc
4