Restore back SwiftPM release/6.0 branch support

Author: ikesyo

Package.swift

@@ -4,6 +4,13 @@
 import PackageDescription
 import Foundation
 
+let swiftPMBranch: String
+#if compiler(>=6.1)
+swiftPMBranch = "release/6.1"
+#else
+swiftPMBranch = "release/6.0"
+#endif
+
 let swiftSettings: [SwiftSetting] = [
     .enableExperimentalFeature("StrictConcurrency"),
     .unsafeFlags(["-strict-concurrency=complete"]),
@@ -23,7 +30,7 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/swiftlang/swift-package-manager.git",
-                 branch: "release/6.1"),
+                 branch: swiftPMBranch),
         .package(url: "https://github.com/apple/swift-log.git",
                  from: "1.5.2"),
         .package(url: "https://github.com/apple/swift-collections",

Sources/ScipioKit/DescriptionPackage.swift

@@ -86,13 +86,23 @@ struct DescriptionPackage: PackageLocator {
 
         let workspace = try Self.makeWorkspace(toolchain: toolchain, packagePath: packageDirectory)
         let scope = makeObservabilitySystem().topScope
+#if compiler(>=6.1)
         self.graph = try await workspace.loadPackageGraph(
             rootInput: PackageGraphRootInput(packages: [packageDirectory.spmAbsolutePath]),
             // This option is same with resolver option `--disable-automatic-resolution`
             // Never update Package.resolved of the package
             forceResolvedVersions: onlyUseVersionsFromResolvedFile,
             observabilityScope: scope
         )
+#else
+        self.graph = try workspace.loadPackageGraph(
+            rootInput: PackageGraphRootInput(packages: [packageDirectory.spmAbsolutePath]),
+            // This option is same with resolver option `--disable-automatic-resolution`
+            // Never update Package.resolved of the package
+            forceResolvedVersions: onlyUseVersionsFromResolvedFile,
+            observabilityScope: scope
+        )
+#endif
         self.manifest = try await workspace.loadRootManifest(
             at: packageDirectory.spmAbsolutePath,
             observabilityScope: scope

Sources/ScipioKit/Producer/PIF/PIFGenerator.swift

@@ -207,8 +207,14 @@ private struct PIFLibraryTargetModifier {
 
         let toolchainLibDir = (try? buildParameters.toolchain.toolchainLibDir) ?? .root
 
+#if compiler(>=6.1)
         settings[.PRODUCT_NAME] = c99Name
         settings[.PRODUCT_MODULE_NAME] = c99Name
+#else
+        settings[.PRODUCT_NAME] = "$(EXECUTABLE_NAME:c99extidentifier)"
+        settings[.PRODUCT_MODULE_NAME] = "$(EXECUTABLE_NAME:c99extidentifier)"
+        settings[.EXECUTABLE_NAME] = c99Name
+#endif
         settings[.TARGET_NAME] = name
         settings[.PRODUCT_BUNDLE_IDENTIFIER] = name.spm_mangledToBundleIdentifier()
         settings[.CLANG_ENABLE_MODULES] = "YES"