[clang] macCatalyst: add SDKSettings.json as a dependency file if its potentially needed by the compiler (PR #177748)

[Steven Wu via cfe-commits]

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@@ -3289,6 +3289,18 @@ void Darwin::addClangTargetOptions(
 
   addClangCC1ASTargetOptions(DriverArgs, CC1Args);
 
+  if (SDKInfo) {
+    // Make the SDKSettings.json an explicit dependency for the compiler
+    // invocation, in case the compiler needs to read it to remap macCatalyst
+    // versions.
+    if ((isTargetMacCatalyst() || TargetVariantTriple) &&
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cachemeifyoucan wrote:

I am thinking we should just remove this constraint. We always use `SDKSettings` when available and we should always make it a dependency.

https://github.com/llvm/llvm-project/pull/177748