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
ref: nodejs/node#62656

Fixes: openssl#30806

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