src: update cares_wrap OpenBSD defines

Move the `#define`s back into `cares_wrap.cc`, as they are part of
the implementation, not the declarations used in `cares_wrap.h`,
and apply the suggestion from
nodejs#38572 (comment)
to make the defines a bit more generic and not check for OpenBSD
specifically.

Refs: nodejs#38572

Author: addaleax

src/cares_wrap.cc

@@ -38,6 +38,19 @@
 #include <vector>
 #include <unordered_set>
 
+#ifndef T_CAA
+# define T_CAA    257 /* Certification Authority Authorization */
+#endif
+
+// OpenBSD does not define these
+#ifndef AI_ALL
+# define AI_ALL 0
+#endif
+#ifndef AI_V4MAPPED
+# define AI_V4MAPPED 0
+#endif
+
+
 namespace node {
 namespace cares_wrap {
 

src/cares_wrap.h

@@ -32,14 +32,6 @@
 # include <arpa/nameser.h>
 #endif
 
-#ifndef T_CAA
-#  define T_CAA    257 /* Certification Authority Authorization */
-#endif
-
-#if defined(__OpenBSD__)
-# define AI_V4MAPPED 0
-#endif
-
 namespace node {
 namespace cares_wrap {