retain full file paths in darshan logs
Right now darshan only records the last N characters (12?) of each file name. This was done mainly because we were overly conservative out of concern for memory overhead.
Modify Darshan to record complete paths, ether by expanding the name field to PATH_MAX or by malloc'ing on demand.
We also need to record CWD as well, so that in post processing we can make a good guess as to the full path even when the application opens relative paths.
realpath() and similar functions are not an option because they walk the path and stat each directory.