GitLab

- match convention of other modules where possible
- avoid trampoline for non-PMPI calls
- resolve underlying symbols at run time
- use symbol name direclty in wrapper

Previously, modules would explicitly disable instrumentation when
ever Darshan core called into the module to shut it down. The
issue is that Darshan core starts shutting down well before modules
do, so there is a time interval where modules could be trying to
instrument data while its not safe to do so.

Now, we expose a function (darshan_core_disabled_instrumentation)
that modules can call to determine if its safe to instrument
data.

1. Use Lustre Module in Darshan
2. Integrate DXLT IO tracing code into one module
3. Add hooks in POSIX and MPI Modules
4. Add Intel copyright
Signed-off-by: Cong Xu <cong.xu@intel.com>

The MAP_OR_FAIL macro is resolving fopen rather than fopen64,
causing a NULL function pointer to be executed in the wrapper
in the case of using Darshan's LD_PRELOAD mechanism.

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

- eliminated 110 SLOC
- untested

- includes regression test for fprintf and fscanf
- apparently you have to wrap __isoc99_fscanf instead of fscanf
  sometimes