[clang] [llvm] [TLI] Add support for reallocarray (PR #114818)

[Matt Arsenault via cfe-commits]

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@@ -3224,6 +3224,13 @@ def AllocA : GNULibBuiltin<"stdlib.h"> {
   let AddBuiltinPrefixedAlias = 1;
 }
 
+// Available in glibc by default since since 2.29 and in GNU mode before.
+def ReallocArray : GNULibBuiltin<"stdlib.h"> {
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arsenm wrote:

The clang builtin change should be separate, and is not tested 

https://github.com/llvm/llvm-project/pull/114818