remove SET_PROC_VALUE() macro

It isn't used anymore since the #2791 merge. It's also unlikely to be
needed again as it wasn't before (its usage was unnecessary).

include/mruby/boxing_nan.h

@@ -87,7 +87,6 @@ typedef struct mrb_value {
 #define SET_INT_VALUE(r,n) BOXNAN_SET_VALUE(r, MRB_TT_FIXNUM, value.i, (n))
 #define SET_SYM_VALUE(r,v) BOXNAN_SET_VALUE(r, MRB_TT_SYMBOL, value.sym, (v))
 #define SET_OBJ_VALUE(r,v) BOXNAN_SET_VALUE(r, (((struct RObject*)(v))->tt), value.p, (v))
-#define SET_PROC_VALUE(r,v) BOXNAN_SET_VALUE(r, MRB_TT_PROC, value.p, v)
 #define SET_CPTR_VALUE(mrb,r,v) BOXNAN_SET_VALUE(r, MRB_TT_CPTR, value.p, v)
 #define SET_UNDEF_VALUE(r) BOXNAN_SET_VALUE(r, MRB_TT_UNDEF, value.i, 0)
 

include/mruby/boxing_no.h

@@ -42,7 +42,6 @@ typedef struct mrb_value {
 #define SET_FLOAT_VALUE(mrb,r,v) BOXNIX_SET_VALUE(r, MRB_TT_FLOAT, value.f, (v))
 #define SET_SYM_VALUE(r,v) BOXNIX_SET_VALUE(r, MRB_TT_SYMBOL, value.sym, (v))
 #define SET_OBJ_VALUE(r,v) BOXNIX_SET_VALUE(r, (((struct RObject*)(v))->tt), value.p, (v))
-#define SET_PROC_VALUE(r,v) BOXNIX_SET_VALUE(r, MRB_TT_PROC, value.p, v)
 #define SET_CPTR_VALUE(mrb,r,v) BOXNIX_SET_VALUE(r, MRB_TT_CPTR, value.p, v)
 #define SET_UNDEF_VALUE(r) BOXNIX_SET_VALUE(r, MRB_TT_UNDEF, value.i, 0)
 

include/mruby/boxing_word.h

@@ -111,7 +111,6 @@ mrb_type(mrb_value o)
 #define SET_INT_VALUE(r,n) BOXWORD_SET_VALUE(r, MRB_TT_FIXNUM, value.i, (n))
 #define SET_SYM_VALUE(r,v) BOXWORD_SET_VALUE(r, MRB_TT_SYMBOL, value.sym, (v))
 #define SET_OBJ_VALUE(r,v) BOXWORD_SET_VALUE(r, (((struct RObject*)(v))->tt), value.p, (v))
-#define SET_PROC_VALUE(r,v) BOXWORD_SET_VALUE(r, MRB_TT_PROC, value.p, v)
 #define SET_UNDEF_VALUE(r) BOXWORD_SET_VALUE(r, MRB_TT_UNDEF, value.i, 0)
 
 #endif  /* MRUBY_BOXING_WORD_H */