using `SCM_UNPACK' in libguile/eval.h to placate compiler

[thi]

during guile-oops compilation (w/ egcs-2.91.66), there are warnings:

"pointer of type `void *' used in arithmetic"

the following small patch to libguile/eval.h wraps SCM args to the C `-'
operator w/ `SCM_UNPACK'.  this makes the warnings go away.

thi


-------------------------------
Index: eval.h
===================================================================
RCS file: /cvs/guile/guile/guile-core/libguile/eval.h,v
retrieving revision 1.39
diff -c -p -w -c -r1.39 eval.h
*** eval.h      2000/03/19 19:01:10     1.39
--- eval.h      2000/03/20 01:42:57
*************** extern long scm_tc16_macro;
*** 162,170 ****
   * tag of 1.  This is called a "gloc".
   */
  
! #define SCM_GLOC_SYM(x) (SCM_CAR((x)-1L))
! #define SCM_GLOC_VAL(x) (SCM_CDR((x)-1L))
! #define SCM_GLOC_VAL_LOC(x) (SCM_CDRLOC((x)-1L))
  
  
  
--- 162,170 ----
   * tag of 1.  This is called a "gloc".
   */
  
! #define SCM_GLOC_SYM(x) (SCM_CAR (SCM_UNPACK (x) - 1L))
! #define SCM_GLOC_VAL(x) (SCM_CDR (SCM_UNPACK (x) - 1L))
! #define SCM_GLOC_VAL_LOC(x) (SCM_CDRLOC (SCM_UNPACK (x) - 1L))