Re: [CRAZY PROPOSAL] Automake should support only GNU make

[Paul Smith]

On Thu, 2011-01-13 at 12:50 -0600, Bob Friesenhahn wrote:
> FYI, ClearCase's clearmake is actually based on GNU make source code. 
> At least it was back when I was using it.

Not that it matters but this is not _quite_ true... otherwise clearmake
would fall under the GPL.

What clearmake used to do was ship with a patched version of GNU make
that added a -E flag, when that flag was given then GNU make would read
the makefiles but instead of actually building anything it would output
an "elaborated" makefile with much of the extra functionality of GNU
make already expanded; for example ifdef etc. would be processed
already, etc.  Clearmake in GNU make mode would exec that patched
version of GNU make with the -E flag, then read the output to get a more
vanilla makefile.  This gave some limited support for GNU make syntax.

However, that model was ditched back in the 1990's sometime.  The last
time I used ClearCase (over 4 years ago now), clearmake simply
implemented some set of GNU make features natively without using any GNU
make preprocessor.  However, the set of features implemented was pretty
weak; something like GNU make 3.76 or so; not much beyond that.  And,
even some 3.76 features there were missing, like auto re-exec
capabilities etc.