[M3devel] INSTALL_ROOT and PKG_USE in cm3.cfg

[Olaf Wagner]

I just wanted to point out why it's call PPC_DARWIN. Now that the
OpenDarwin project has closed down, it may indeed seem strange.
But many of the names can only be understood based on their history.
I'm with you that they are neither systematic nor intuitive.
I think I could even be persuaded to support a general renaming,
if the scheme and concepts are well considered before.

Quoting Jay <jayk123 at hotmail.com>:

> The PPC_DARWIN port has an optional dependency on X Windows..is that  
>  available for plain Darwin or only with Mac OS X?

Yes. Actually the X in X Windows and MacOS X refer to completely different
things. MacOS X does not support X Windows out of the box, it uses
Aqua as GUI.

> I was surprised by "Darwin", therefore would be.. :)
That's why I tried to explain it ;-)

> LINUX, LINUXELF, LINUXLIBC6? Please.
> Couldn't Linux have been recycled for LINUXLIBC6?Does anyone have   
> Linux 1.2 around?

It could be done now, but it couldn't when it was created.

> Are the older FreeBSD ABIs so inferior that it is worth having newer  
>  ones? They didn't have pthreads back then and they do now?

There are ABI changes with every major release of FreeBSD (and also
Linux, Solaris, and other operating systems if I am not much mistaken).
Of course, everyone strives for compatibility of the often used and
most important interfaces, but there is a grey zone where data
structures common to the kernel and userland are touched, and they
need to be updated (in order to not hinder improvement) more often
than you'd think. If such an update annoys or disturbs users often
enough, new interface abstractions tend to appear that should
avoid the problem for future releases (for example, changes of the
jmp_buf structure break threading code --> new interfaces for thread
context access are defined). The M3 runtime is somewhat special and
differs from the C runtime in that it makes use of quite a number of not
always well-defined system interfaces. We also try to eliminate these
dependencies (VM calls, jmp_buf structure, whole threading, ...)

Actually I think I was the first one to port any pthread package to
FreeBSD (when working for a company building POS solutions, but we could
never release the code) back in the 1.5 and 2.x days. I used a pthreads
implementation by Frank Mueller.
Official pthread support came much later.

Olaf
-- 
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