SIGSEGV in initdb

While updating my local copy to current sources and running initdb I got a 
SIGSEGV at bootstrap.c:465 while adding template1 to pg_database.

This is because RelationBuildDesc in relcache.c returns a NULL at line 766. 
The comments above this line say:

find the tuple in pg_class corresponding to the given relation id
if no such tuple exists, return NULL

(the relation is pg_database)

There seems to be some kind of error in the order in which the database is 
bootstrapped and the system tables are created and filled.

Any ideas?


Cheers,

Jeroen