[clang] [lld] [llvm] Conditionalize use of POSIX features missing on WASI/WebAssembly (PR #92677)

[James Y Knight via llvm-commits]

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@@ -252,13 +257,21 @@ std::error_code Process::FixupStandardFileDescriptors() {
 
     if (NullFD == StandardFD)
       FDC.keepOpen();
+#if defined(__wasi__)
+    else // WASI does not have `dup2` by design. Return EBADF.
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jyknight wrote:

Does wasi have /dev/null? If not, this whole function is pointless. If so, that could be opened directly, instead. Actually, given the number of changes here for wasi, shouldn't wasi just have its own llvm/lib/Support/WASI/Process.inc file?

https://github.com/llvm/llvm-project/pull/92677