As part of the Performance Co-Pilot Log Import API (see LOGIMPORT(3)), pmiErrStr translates error codes
returned from the other routines in the Log Import library into printable error messages.
code would normally have a negative value. As a special case, if code is -1 then the error code returned
from the last routine called in the LOGIMPORT library for this context will be used.
The pmiErrStr_r function does the same, but stores the result in a user-supplied buffer buf of length
buflen, which should have room for at least PMI_MAXERRMSGLEN bytes.
The set of possible error codes and messages is all those defined by pmErrStr(3) and PCPIntro(3), plus
the additional ones defined in <pcp/import.h> with error code names of the form PMI_ERR_....