aix: disable sendmmsg/recvmmsg

AIX header files don't properly expose sendmmsg/recvmmsg function
declarations. Disable these functions to avoid implicit declaration
errors with clang 16+.

This issue was discovered when building Node.js with clang.

CLA: trivial
Fixes: 52cd2a4 "Enable send-/recvmmsg for AIX >= 7.2 and disable SUPPORT_LOCAL_ADDR."
References: nodejs/node#62656
Resolves: #30806

Reviewed-by: Matt Caswell <[email protected]>
Reviewed-by: Eugene Syromiatnikov <[email protected]>
MergeDate: Sun Apr 26 12:02:58 2026
(Merged from #30832)

(cherry picked from commit 646aae6)

Author: abmusse

crypto/bio/bss_dgram.c

@@ -68,8 +68,8 @@
 #undef NO_RECVMMSG
 #define NO_RECVMMSG
 #endif
-#if defined(_AIX) && !defined(_AIX72)
-/* AIX >= 7.2 provides sendmmsg() and recvmmsg(). */
+#if defined(_AIX)
+/* AIX header files don't properly expose sendmmsg/recvmmsg declarations */
 #undef NO_RECVMMSG
 #define NO_RECVMMSG
 #endif