[Signals] Exclude dladdr for AIX after llvm#123879

Widely supported but missing on AIX
https://www.austingroupbugs.net/view.php?id=993

Author: MaskRay

llvm/lib/Support/Unix/Signals.inc

@@ -812,7 +812,7 @@ void llvm::sys::PrintStackTrace(raw_ostream &OS, int Depth) {
   OS << "Stack dump without symbol names (ensure you have llvm-symbolizer in "
         "your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point "
         "to it):\n";
-#if HAVE_DLOPEN
+#if HAVE_DLOPEN && !defined(_AIX)
   int width = 0;
   for (int i = 0; i < depth; ++i) {
     Dl_info dlinfo;