Modify main.c to call geteuid instead of getuid about pwauth HOT 1 CLOSED

The purpose of this test it to ensure that pwauth was invoked by Apache, not by 
some other program, so it checks the REAL uid to see if it is whatever Apache 
is configured to run under, and refuses to run if invoked by any other user.  
This is not really an incredibly important security feature, but it's one more 
layer of paranoia in a program that takes paranoia seriously.

Checking the EFFECTIVE uid instead disables this check completely. Pwauth's 
effective uid is always root, so the check will never fail. If you want to 
disable this check you can do so more cleanly by undefining SERVER_UIDS in 
config.h.