plmerge crash in latest trunk

[David Chisnall]

Since my last svn update I got errors complaining that an NSZone- 
related symbol was missing (what is the reason for this?  Breaking the  
ABI is not considered friendly.).  As a result I've had to recompile  
everything.  This wouldn't be a major problem, except that plmerge  
keeps crashing.

This is a back trace from the last core it dumped:

#0  0x28449105 in objc_msg_lookup (receiver=0xa5a5a5a5, op=0x283b0aa0)  
at sendmsg.c:226
#1  0x280fac8d in GSIMapBucketForKey (map=0x28ae979c, key=
      {addr = 2779096485, obj = 0xa5a5a5a5, nso = 0xa5a5a5a5}) at  
GSIMap.h:341
#2  0x280faef9 in GSIMapNodeForKey (map=0x28ae979c, key=
      {addr = 2779096485, obj = 0xa5a5a5a5, nso = 0xa5a5a5a5}) at  
GSIMap.h:579
#3  0x280fb701 in -[GSDictionary objectForKey:] (self=0x28ae9798,  
_cmd=0x28410e48,
    aKey=0xa5a5a5a5) at GSDictionary.m:344
#4  0x28274dbb in -[NSUserDefaults objectForKey:] (self=0x28a29828,  
_cmd=0x284110a8,
    defaultName=0x28410390) at NSUserDefaults.m:1020
#5  0x2827483a in -[NSUserDefaults arrayForKey:] (self=0x28a29828,  
_cmd=0x28410e00,
    defaultName=0x28410390) at NSUserDefaults.m:937
#6  0x28271763 in updateCache (self=0x28a29828) at NSUserDefaults.m:109
#7  0x28272f0d in +[NSUserDefaults standardUserDefaults]  
(self=0x28410dc0, _cmd=0x283d0e18)
    at NSUserDefaults.m:632
#8  0x2819ab46 in -[NSDictionary writeToFile:atomically:]  
(self=0x28a297f8, _cmd=0x804aab8,
    path=0x28aa7268, useAuxiliaryFile=1 '\001') at NSDictionary.m:984
#9  0x0804945c in main () at plmerge.m:139

Any thoughts?

David