Disable USE_USER_EVENT_LOGGING by default in the source file.
This is better enabled via configure, compile_cmd or Makefile.
Also, when USE_USER_EVENT_LOGGING is unset then don't do any
event logging activities at all, such as opening log files,
or initializing event logging threads.
Move AC_USE_SYSTEM_EXTENSIONS near the top to prevent autoconf warnings.
Only warn for unset SAC2BASE when building sac4snet.
Add option --disable-setaffinity.
Merge remote-tracking branch 'upstream/master'
Undo changes to AC_USE_SYSTEM_EXTENSIONS which broke MPI.
Add a function C4SNetGetType to obtain the basic type of a field.
Add a function C4SNetGetString to convert an array of CTYPE_char
or CTYPE_uchar to a proper nul-terminated C string.
Add comments in the C4SNet.h header file to briefly explain each
function.
Report layout of partially matched synchro-cells when SNetVerbose is
TRUE.
Report routing problems for parallel choice entities in great detail to
facilitate debugging S-Net programs.
Two important bug fixes for race conditions in S-Net reference counting.
Make fix for two race conditions dependent on presence of
HAVE_SYNC_ATOMIC_BUILTINS.  Add comments to explain the situation.
Merge pull request #47 from gijsbers/master

Improve configure.ac, logging and C4SNet