The Question is:
Where is IMP$M_ASSUME_DEFPRIV for the SYS$PERSONA_CREATE service defined ?
The Answer is :
In the system definition module IMPDEF.
From Compaq C on OpenVMS Alpha V7.2-1:
#define IMP$M_ASSUME_DEFPRIV 0x8
The IMPDEF module and the IMP$M_ASSUME_DEFPRIV symbol are available on
OpenVMS V6.2 and later, but the language installation may not have been
run since the OpenVMS V6.2 upgrade (various language kits will extract
and format the system definitions as part of the installation), or the
language tool(s) may not have been available to pick up the definition
for the particular release.