Fix compilation on not yet released SBCL

[shamazmazum]

Fix compilation on SBCL after this commit:

sbcl/sbcl@8438fc57b

[github-actions]

Coverage report

Source file	Covered expressions	Total expressions	%	Covered branches	Total branches	%
baseinfo.lisp	58	94	61.7	8	10	80.0
enum.lisp	35	57	61.4	1	2	50.0
ffi.lisp	76	136	55.9	3	4	75.0
field.lisp	33	41	80.5	2	4	50.0
function.lisp	877	1163	75.4	44	66	66.7
gvalue.lisp	143	308	46.4	35	80	43.8
init.lisp	26	61	42.6	4	6	66.7
object.lisp	199	500	39.8	11	22	50.0
properties.lisp	52	59	88.1	1	2	50.0
repository.lisp	57	168	33.9	0	0	-
signal.lisp	66	113	58.4	6	14	42.9
struct.lisp	152	215	70.7	3	6	50.0
trampoline.lisp	11	24	45.8	0	4	0.0
typelib.lisp	7	43	16.3	0	2	0.0
types.lisp	3	13	23.1	0	0	-
utilities.lisp	16	26	61.5	2	2	100.0