[clang] [clang] Restrict -Wnrvo to C++ code only. (PR #157059)

[via cfe-commits]

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@@ -223,6 +223,7 @@ Deprecated Compiler Flags
 Modified Compiler Flags
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 - The `-gkey-instructions` compiler flag is now enabled by default when DWARF is emitted for plain C/C++ and optimizations are enabled. (#GH149509)
+- The `-Wnrvo` compiler flag will not apply for C language.
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Sirraide wrote:

That’s probably the easiest solution, yeah

https://github.com/llvm/llvm-project/pull/157059