[Exim] Encoding the name of EXIM_USER instead of its user-id…

Hello,
If EXIM_USER is not numeric currently buildconfig.c uses getpwnam() to
look up its uid and hardcodes this value into the exim-binary. What is
the reason for this, is there a race-condition somewhere?

I am asking because I need to encode the name instead of uid for
binary redistribution, on installation a exim-user would be allocated
with a non-static id.

Compilation would need to work on systems without an exim-user
present, too.
                 cu andreas