[libunwind] [libunwind][AIX] Remove weak definition "__xlcxx_personality_v0" (PR #112436)

[Hubert Tong via cfe-commits]

================
@@ -2126,42 +2125,34 @@ bool UnwindCursor<A, R>::getInfoFromTBTable(pint_t pc, R &registers) {
     // function __xlcxx_personality_v0(), which is the personality for the state
     // table and is exported from libc++abi, is directly assigned as the
     // handler here. When a legacy XLC++ frame is encountered, the symbol
-    // is resolved dynamically using dlopen() to avoid hard dependency from
-    // libunwind on libc++abi.
+    // is resolved dynamically using dlopen() to avoid a hard dependency of
+    // libunwind on libc++abi in cases such as non-C++ applications.
 
     // Resolve the function pointer to the state table personality if it has
-    // not already.
+    // not already done.
     if (xlcPersonalityV0 == NULL) {
       xlcPersonalityV0InitLock.lock();
       if (xlcPersonalityV0 == NULL) {
-        // If libc++abi is statically linked in, symbol __xlcxx_personality_v0
-        // has been resolved at the link time.
-        xlcPersonalityV0 = &__xlcxx_personality_v0;
+        // Resolve __xlcxx_personality_v0 using dlopen().
+        const char libcxxabi[] = "libc++abi.a(libc++abi.so.1)";
----------------
hubert-reinterpretcast wrote:

Minor nit: No need for a local stack copy of the string.
```suggestion
        const char *libcxxabi = "libc++abi.a(libc++abi.so.1)";
```

https://github.com/llvm/llvm-project/pull/112436