[clang] [clang][RISCV] Add big-endian RISC-V target support (PR #165599)

[Eli Friedman via cfe-commits]

================
@@ -1732,16 +1734,20 @@ static void findRISCVBareMetalMultilibs(const Driver &D,
             .flag(Twine("-march=", Element.march).str())
             .flag(Twine("-mabi=", Element.mabi).str()));
   }
+
+  std::string EndiannessSuffix = TargetTriple.isLittleEndian() ? "" : "be";
   MultilibSet RISCVMultilibs =
       MultilibSetBuilder()
           .Either(Ms)
           .makeMultilibSet()
           .FilterOut(NonExistent)
-          .setFilePathsCallback([](const Multilib &M) {
+          .setFilePathsCallback([EndiannessSuffix](const Multilib &M) {
----------------
efriedma-quic wrote:

```suggestion
          .setFilePathsCallback([&EndiannessSuffix](const Multilib &M) {
```

https://github.com/llvm/llvm-project/pull/165599