* Result of round has same value as lround but keeps value in FPU.

* Also add missing fail-safe wrapper.

* Also cleans up minor issues.

for serial netCDF library usage.

* This exercises the code for which a bug was introduced in r3181 and
  fixed in r3200.

* malloc et al. can return NULL on zero-size allocations.
* this commit also reverts the dubious calling of calloc by xmalloc.