deb: recommend the correct hostmot2 package

The correct name for the hostmot2 firmware package to Recommend is
"hostmot2-firmware-all".

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
Merge remote-tracking branch 'seb-gh/seb/2.6/fix-recommends-hm2' into 2.6

Signed-off-by: Jeff Epler <jepler@unpythonic.net>
Merge remote-tracking branch 'origin/2.6'

Signed-off-by: Jeff Epler <jepler@unpythonic.net>

Conflicts:
	debian/configure
hm2 sample config: set HOME_SEQUENCE

This is just for the convenience of getting a "Home All" button in Axis.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
Merge remote-tracking branch 'origin/2.6'
interp: use strings to avoid buffer hell

I ended up here because clang warned about 'strncat(cmd, buf, sizeof(buf))'
-- strncat is notoriously difficult to use.  This usage is wrong, and
related code must be prepared to deal with a non-NULL-terminated character
array (which related code was not).

Use C++ strings instead, until it becomes inconvenient to (the place
where the string needs to be split at newlines)
hal: an "increased" pin for thread time

.. this way you can trigger on "tmax-increased" when scoping for
overruns
rtapi: remove support for rtlinux 3.x

No one answered the call for maintainers.  In fact, there's no sign that
rtlinux even exists for modern linux versions.
rtapi: drop support for rtai "24.x"

.. this version of rtai was for kernel 2.4.x, which are no longer
supported.
rtapi: drop support for alternate math libs

ever since we hardcoded the loading of rtai_math years ago, we have
never exercised the code path where we allow the use of diet or glibc
math libraries in kernel space.  Drop the related code.
configure: drop never-used RTAI3_MOD variable

this may once have been used to dynamically list the rtai modules to be
loaded, but this list has been static for a long time.
uspace: don't let ctrl-z stop realtime

.. if the rtapi_app process is the head of its own process group,
it is not subject to being stopped by ctrl-z in the terminal where it
was started.
configure: don't require linux/version.h

This has been a legacy/unsupported header file for a long time, and
according to memleak is finally gone in kernels somewhere in the 3.x
days.  We have long looked at several alternative filenames to actually
find the magic constants, but for some reason required that the
version.h header exist at a certain spot even though we didn't use it
except as a last resort.
hostmot2: support boards on spi interface

.. for uspace systems with /dev/spidev.  This is mildly tested on odroid
u3 with a 7i43 custom firmware and with a real 7i90.

Note that on many systems out there, including odroid, /dev/spidev is lousy
for realtime performance.  Some kernel-side changes, available at
https://github.com/jepler/odroid-linux.git in brnach odroid-3.8.13-rt
give good performance on my odroid u3 system.