opt: avoid function pointer arithmetic

Same fix as we used for ccan/typesafe_cb.

diff --git a/ccan/opt/opt.h b/ccan/opt/opt.h
index 539a0a664de155962f3d2efdf116eca52d25fcee..9075ceed37e8c0e61e0dedb1a94df6ba4efede3f 100644 (file)
--- a/ccan/opt/opt.h
+++ b/ccan/opt/opt.h
@@ -315,7 +315,7 @@ struct opt_table {
 /* Resolves to the four parameters for non-arg callbacks. */
 #define OPT_CB_NOARG(cb, arg)                          \
        OPT_NOARG,                                      \
-       cast_if_any(char *(*)(void *), (cb), (cb)+0,    \
+       cast_if_any(char *(*)(void *), (cb), 0?(cb):(cb),\
                    char *(*)(typeof(*(arg))*),         \
                    char *(*)(const typeof(*(arg))*),   \
                    char *(*)(const void *)),           \
@@ -324,11 +324,12 @@ struct opt_table {
 /* Resolves to the four parameters for arg callbacks. */
 #define OPT_CB_ARG(cb, show, arg)                                      \
        OPT_HASARG, NULL,                                               \
-       cast_if_any(char *(*)(const char *,void *), (cb), (cb)+0,       \
+       cast_if_any(char *(*)(const char *,void *), (cb), 0?(cb):(cb),  \
                    char *(*)(const char *, typeof(*(arg))*),           \
                    char *(*)(const char *, const typeof(*(arg))*),     \
                    char *(*)(const char *, const void *)),             \
-       cast_if_type(void (*)(char buf[], const void *), (show), (show)+0, \
+       cast_if_type(void (*)(char buf[], const void *), (show),        \
+                    0?(show):(show),                                   \
                     void (*)(char buf[], const typeof(*(arg))*))
 
 /* Non-typesafe register function. */