Current CVS tip segfaulting

Hackers,

In current (as of a couple hours ago) clean CVS tip sources, without any
of my local changes, I'm getting a postmaster segfault when trying to
connect to a non existant database. The generated core file does not
seem to contain any useful information. The first time I saw this I
managed to PANIC the system -- I can't seem to be able to reproduce that
part.

(Newly built on an empty vpath, so this should be a case of "make
distcleaning" ...)

Core was generated by `postgres: alvherre asd [local] startup
'.
Program terminated with signal 11, Segmentation fault.

warning: current_sos: Can't read pathname for load map: Input/output error

Reading symbols from /lib/libz.so.1...done.
Loaded symbols for /lib/libz.so.1
Reading symbols from /lib/libreadline.so.4.3...done.
Loaded symbols for /lib/libreadline.so.4.3
Reading symbols from /lib/libncurses.so.5...done.
Loaded symbols for /lib/libncurses.so.5
Reading symbols from /lib/libcrypt.so.1...done.
Loaded symbols for /lib/libcrypt.so.1
Reading symbols from /lib/libresolv.so.2...done.
Loaded symbols for /lib/libresolv.so.2
Reading symbols from /lib/libnsl.so.1...done.
Loaded symbols for /lib/libnsl.so.1
Reading symbols from /lib/libdl.so.2...done.
Loaded symbols for /lib/libdl.so.2
Reading symbols from /lib/tls/libm.so.6...done.
Loaded symbols for /lib/tls/libm.so.6
Reading symbols from /lib/tls/libc.so.6...done.
Loaded symbols for /lib/tls/libc.so.6
Reading symbols from /lib/libgpm.so.1...done.
Loaded symbols for /lib/libgpm.so.1
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
Reading symbols from /lib/libnss_files.so.2...done.
Loaded symbols for /lib/libnss_files.so.2
Reading symbols from /usr/lib/gconv/ISO8859-15.so...done.
Loaded symbols for /usr/lib/gconv/ISO8859-15.so
Reading symbols from /usr/lib/gconv/ISO8859-1.so...done.
Loaded symbols for /usr/lib/gconv/ISO8859-1.so
0x00000000 in ?? ()
(gdb) bt
#0 0x00000000 in ?? ()

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"The only difference is that Saddam would kill you on private, where the
Americans will kill you in public" (Mohammad Saleh, 39, a building contractor)