[PATCH] udev - safer string handling - part two

[PATCH] udev - safer string handling - part two

As promised, here is the next round. We provide in addition to the
already used macros:

  strfieldcpy(to, from)
  strfieldcat(to, from)

the corresponding friends, if the size of the target is not known and
must be provided by the caller:

  strnfieldcpy(to, from, maxsize)
  strnfieldcat(to, from, maxsize)

and switch nearly all possibly unsafe users of strcat(), strncat(),
strcpy() and strncpy() to these safer macros.

The last known remaining issue seems the use of sprintf() and
snprintf(). I will take on it later today or tomorrow.