[DNM] Diagnostic prints for CI debugging

Sources/SwiftDriver/Toolchains/DarwinToolchain.swift

@@ -373,9 +373,10 @@ public final class DarwinToolchain: Toolchain {
     frontendTargetInfo: FrontendTargetInfo,
     driver: inout Driver
   ) throws {
+    print("WWW: Adding platform-specific flags.")
     guard let sdkPath = frontendTargetInfo.sdkPath?.path,
           let sdkInfo = getTargetSDKInfo(sdkPath: sdkPath) else { return }
-
+    print("WWW: ...")
     commandLine.append(.flag("-target-sdk-version"))
     commandLine.append(.flag(sdkInfo.sdkVersion(for: frontendTargetInfo.target.triple).sdkVersionString))
 
@@ -406,6 +407,7 @@ public final class DarwinToolchain: Toolchain {
     // If not specified otherwise, we should use the same triple as -target
     if !driver.parsedOptions.hasArgument(.disableClangTarget) &&
         driver.isFrontendArgSupported(.clangTarget) {
+      print("Frontend supports '-clang-target'")
       // The common target triple for all Clang dependencies of this compilation,
       // both direct and transitive is computed as:
       // 1. An explicitly-specified `-clang-target` argument to this driver invocation
@@ -419,6 +421,7 @@ public final class DarwinToolchain: Toolchain {
 
       commandLine.appendFlag(.clangTarget)
       commandLine.appendFlag(clangTargetTriple)
+      print("Added '-clang-target \(clangTargetTriple)'")
     }
   }
 }

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -3641,6 +3641,8 @@ final class SwiftDriverTests: XCTestCase {
     XCTAssertEqual(plannedJobs.count, 2)
     XCTAssertTrue(plannedJobs[0].commandLine.contains(.flag("-target")))
     XCTAssertTrue(plannedJobs[0].commandLine.contains(subsequence: [.flag("-clang-target"), .flag("arm64-apple-ios13.0")]))
+
+    print("COMMAND_LINE2: \(plannedJobs[0].commandLine.joinedUnresolvedArguments)")
 #endif
   }