[clang] [clang][ssaf] Fix building on gcc-7 and MinGW/Cygwin (PR #181812)

[Balázs Benics via cfe-commits]

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@@ -27,6 +27,8 @@
 using namespace clang;
 using namespace ssaf;
 
+LLVM_INSTANTIATE_REGISTRY(llvm::Registry<MockSerializationFormat::FormatInfo>)
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steakhal wrote:

Isn't the problem inside the `LLVM_INSTANTIATE_REGISTRY` macro then? So I guess one would need to fix the macro itself because AFAIK that is the preferred way, right? Otherwise why would it exist?

https://github.com/llvm/llvm-project/pull/181812