[clang] [RISCV] Merging RISCVToolChain and BareMetal toolchains (PR #118809)

[Craig Topper via cfe-commits]

================
@@ -291,6 +365,36 @@ BareMetal::OrderedMultilibs BareMetal::getOrderedMultilibs() const {
   return llvm::reverse(Default);
 }
 
+ToolChain::CXXStdlibType BareMetal::GetDefaultCXXStdlibType() const {
+  if (getTriple().isRISCV()) {
----------------
topperc wrote:

Could this be simplified to

```
if (getTriple().isRISCV() && GCCInstallation.isValid())
  return ToolChain::CST_Libstdcxx;

return ToolChain::CST_Libcxx;
```

https://github.com/llvm/llvm-project/pull/118809