Define ISC_ATTR_UNUSED macro for __attribute__((__unused__))

The ISC_ATTR_UNUSED macro was missing in BIND 9.18, which
complicated things when backporting merge requests from main.
As __attribute__((__unused__)) is ubiquitous, just define the
macro.

diff --git a/lib/isc/include/isc/attributes.h b/lib/isc/include/isc/attributes.h
index abe615223e9f8de7c285d31430ead1f8f49fc556..f38a558552eafaee09866b212c559585f07e1511 100644 (file)
--- a/lib/isc/include/isc/attributes.h
+++ b/lib/isc/include/isc/attributes.h
@@ -80,3 +80,5 @@
 #define ISC_ATTR_MALLOC_DEALLOCATOR(deallocator)
 #define ISC_ATTR_MALLOC_DEALLOCATOR_IDX(deallocator, idx)
 #endif /* HAVE_FUNC_ATTRIBUTE_MALLOC */
+
+#define ISC_ATTR_UNUSED __attribute__((__unused__))