Here is the fix I recommend.  Apply this and rebuild libc.

*** src/sys/sys/exec.h.orig	Thu Jan 23 11:34:43 1997
--- src/sys/sys/exec.h	Fri May  9 10:22:12 1997
***************
*** 61,70 ****
  };
  
  /*
!  * Address of ps_strings structure (in user space).
   */
  #define	PS_STRINGS \
  	((struct ps_strings *)(USRSTACK - sizeof(struct ps_strings)))
  
  /*
   * Below the PS_STRINGS and sigtramp, we may require a gap on the stack
--- 61,78 ----
  };
  
  /*
!  * Address of ps_strings structure.  In user space, we get this
!  * from a variable set in crt0 (because the stack address may not
!  * be constant across all machines where the program might run).
!  * In the kernel, this is just a constant.
   */
+ #ifdef	_KERNEL
  #define	PS_STRINGS \
  	((struct ps_strings *)(USRSTACK - sizeof(struct ps_strings)))
+ #else	/* _KERNEL */
+ extern struct ps_strings *__ps_strings;
+ #define	PS_STRINGS __ps_strings;
+ #endif	/* _KERNEL */
  
  /*
   * Below the PS_STRINGS and sigtramp, we may require a gap on the stack