[clang] [RISCV] Install sifive_vector.h to riscv-resource-headers (PR #66330)

[Brandon Wu via cfe-commits]

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@@ -623,6 +623,11 @@ install(
   EXCLUDE_FROM_ALL
   COMPONENT riscv-resource-headers)
 
+install(
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4vtomat wrote:

Yes, we are missing from add_header_target("riscv-resource-headers" "${riscv_files};${riscv_generated_files}").
I think we can just put sifive_vector.h in riscv_files, I'll have another patch for it, thanks!

https://github.com/llvm/llvm-project/pull/66330