[Qt-creator] parallel processing in make

[Coda Highland]

> Actually, if Creator can do it with QThreadPool, why can't qmake
> do it with QThreadPool?  Then my Makefile would always have
> the right -j argument for the machine it was created on.

Because you can't define the -j flag in the makefile itself; it's only
recognized as an environment variable or as a command line parameter.

> Actually, I think he meant: "j argument present but not set".
> Such as "make -j". And yes, that should automagically use all available
> cores.

As I described earlier, it simply does everything in parallel. It
doesn't restrict how many processes it spawns, which for any sizable
project means you're going to have dozens of compilers all at each
others' throats. "make -j" is a bad idea and in my opinion shouldn't
exist.

/s/ Adam