docs/ub info: add 'Reporting an error'

take out some guesswork.
man/hal_create_thread, rtapi_task_new: doucment new parameters
deb: fix a syntax error in control.in

Thanks to Kent Reed for reporting this bug.
realtime.in:  fix shm checking

Test for shmdrv applicability updated (again :P)
realtime:  thorough shmdrv checks; DEBUG value always decimal

Unload() was leaving the shmdrv module behind when segments were
allocated, even if not open.

FIXME:  this case needs to be clarified; see
    https://github.com/zultron/linuxcnc/issues/36

CheckShm() now takes an argument for which specific shmdrv check:
     -l: return success if shmdrv device exists
     -w: wait for shmdrv to be loaded; return success if loaded
     -a: return success if any segments allocated
     -o: return success if any segments open

Also, always set $DEBUG to some decimal number.
realtime.in:  more thorough CheckStatus() checks

user threads, check for running rtapi_app and rtapi_msgd

detailed shmdrv checks
realtime:  revert extended shmdrv tests

We don't care who's using shmdrv, just try to remove it at unload
time, and move on whether it succeeds or fails.
Fix gcc multilib bug in precise

http://gcc.gnu.org/ml/gcc/2012-02/msg00314.html

- Check for bug in configure script
- Pass fix through Makefile.inc to Makefile to rtapi/xeno_math/Makefile
- Call kbuild with fix