ArcticFox browser on NetBSD 10.1 sparc64

Hi all!

A moment long awaited, after having worked for more than 6 years of 
working on ArcticFox.
It starts, displays and work on NetBSD sparc64! (NetBSD ppc32 too, btw).

Challenges were not easy and while some fixes kept in flowing the target 
also moved.

v47.2 is out today and brings back support! Binary provided for the curious.

Screenshot shows it running on NetraT1!


Only real drawback is the core NetBSD issue: a build means always a full 
build, it reconfigures always from scratch. Other OSs (including OpenBSD 
and FreeBSD) are not affected by this. It makes testing very hard.

To give an idea: on my 2-core amd64 NetBSD build it takes 2 hours, on my 
G4 1.33GHz iBook it takes 4-5hours, on my Netra T1 Ultra IIe 500Mhz it 
takes 40 hours!
Change a single line and all starts again! For build farms it is not 
detected, but for development it is a hard take.

Apart that for some reason compiling on UltraSPARC appears quite slow, 
it is a NetBSD issue that should be fixed, if somebody wants to help.
alexnia suggested a shell issue and apparently hard-replacing sh with 
bash fixes it, I never tried since it is a dangerous thing to do.

Riccardo