log_memusage: fflush() our memory log file

v3.0.1 - simple tag for same version used at April 2023 ISS conference.

stdatomic.h portability

fix for dlsym() calling calloc (infinite loop), portability without reallocarray

Merge pull request #2 from NCAR/liblogmemusage

ready to merge this branch

wrapping up v3.0.0, malloc wrapping disabled by default as is still WIP

cleanup

cleanup

refactor malloc wrapper with malloc_usable_size()

malloc WIP

WIP: malloc wrapper

towards malloc wrapper

use C++ for peak_memusage wrapper

dlopen() changes