Clarify install docs re: sim/uspace

[SebKuzminsky]

Our install docs are not sufficiently clear about how you can run sim/uspace debs on vanilla kernels for simulating your gcode programs, but that's a useful and valuable way to run linuxcnc.

[jepler]

we also need to discuss how uspace can be used with rtai and xenomai realtime in master

[rredford]

There is rather ugly workaround to get linuxcnc installed on your system. From https://forum.linuxcnc.org/9-installing-linuxcnc/32941-linuxcnc-on-debian-stretch?start=30#96331 :

Error is : Required version of libboost-python is not in stretch repository.

Temporarily point to jessie repo to install such library.

sudo nano /etc/apt/sources.list with nano to contain:
deb http://ftp.us.debian.org/debian jessie main
save then do those 2 commands:
sudo apt-get update
sudo apt-get install linuxcnc-uspace

Now remove the pointer to jessie in sources.list then do
sudo apt-get update

[jepler]

There is rather ugly workaround to get linuxcnc installed on your system. From https://forum.linuxcnc.org/9-installing-linuxcnc/32941-linuxcnc-on-debian-stretch?start=30#96331 :

As far as I know, this is not correct. The LinuxCNC package for stretch served from linuxcnc.org should not require any packages not in debian stretch OR served from linuxcnc.org. As far as the boost requirement goes, the one from stretch is used.

That poster noted that they are using a a LinuxCNC package that they built themselves from source, so it's possible that they have different dependencies; the information is also over a year old, and improvements to the Debian packaging for stretch have probably occurred since then.

[rredford]

Mine is just from repos. I suspect if I build it on system the such workaround isn't needed. We might want to make 2 repo versions, one for linuxcnc system, and one for other linux systems, for sim only.

[andypugh]

It's been more than 8 years, but...