Convenience variables and functions for makefiles

[Phi Debian]

Hi All,

I am not subscribed (yet?) to the help-make, I am in the bug-make, so
when replying make sure I am in the cc list.

My question is, is there some well knows .mk sample files that define
commonly used features implemented as variables (and then as functions
eventually).

I am asking because I found make very powerfull, and with all the
fondamentals to buildup more powerfull construct, a bit like if make
implement all the basic section2, and the upper lever section3 is to
be defined in a .mk

For instance I endup writing a lot of tiny obvious utilities that I am
sure other have written in the past like

- defining empty, space, comma

- Ignoring a variable that was set in the make invocation environment
(dangerouse variable to use if exported).
check if a variable was explicilty given in the runstring.

- Accept a variable from the runstring in a comma separated list be
normalise it as a space separated list.
I.e typing make x=a b c' is the same as make x=a,b,c

The given examples here focus on the runstring but I got many other
vras/func not related to runstring but as trivial.

So I wonder if there is a site, or a git repos, with such definitions,
we could call a library, i.e makelib.mk that would define a set of
utilities.

Thanx in advance,
Cheers,
Phi