GitLab

POSIX_F_OPEN_TIMESTAMP is now POSIX_F_OPEN_START_TIMESTAMP
POSIX_F_CLOSE_TIMESTAMP is now POSIX_F_CLOSE_END_TIMESTAMP

I also added POSIX_F_OPEN_END_TIMESTAMP and
POSIX_F_CLOSE_START_TIMESTAMP, so we can better understand how
long open and close phases are for some applications.

this includes defining an example logutils function for
aggregating null records into a single shared null record (needed
for darshan-merge utility)

This is needed to distinguish between log files generated with
the same job id (i.e., for jobs that have multiple steps)

This function can be called by modules to allow FS-specific
modules to gather data for a given file path/file descriptor.
Currently integrated into POSIX and STDIO modules.

- remaining items are tracked in gitlab issues

- untested

There are cases where lustre stripe info is not available the
first time a given file is opened (e.g., when using the
llapi_file_create call). So, now we call into the lustre module
every time a file is opened to give the module a chance to gather
data.

some bugs were causing the regression tests to fail when using
LD_PRELOAD instrumentation method

- eliminated 110 SLOC
- untested

fixed bugs that prevented record names from mapping to file systems in darshan-util; also fixed thread safety and deadlock issues