Android: import new Android overlay in more places (#8115)

Also, fix one test and add the right path for `touch` in the plugin
tests.

@dschaefer2, I use this patch to build both natively on Android and
[cross-compile for my Android
CI](https://github.com/finagolfin/swift-android-sdk/blob/cb93bf31adeefba44ce8041a90f6c88f7241ae2d/swift-android-ci.patch#L114).
It would be good to get it in before the upcoming 6.1 branch: should be
easy to review as it touches nothing outside Android and makes simple
changes for Android.

Author: finagolfin

Fixtures/Miscellaneous/PluginGeneratedResources/Plugins/Generator/plugin.swift

@@ -1,12 +1,18 @@
 import PackagePlugin
 
+#if os(Android)
+let touchExe = "/system/bin/touch"
+#else
+let touchExe = "/usr/bin/touch"
+#endif
+
 @main
 struct GeneratorPlugin: BuildToolPlugin {
     func createBuildCommands(context: PluginContext, target: Target) async throws -> [Command] {
         return [
             .prebuildCommand(
                 displayName: "Generating empty file",
-                executable: .init("/usr/bin/touch"),
+                executable: .init(touchExe),
                 arguments: [context.pluginWorkDirectory.appending("best.txt")],
                 outputFilesDirectory: context.pluginWorkDirectory
             )

Fixtures/Miscellaneous/Plugins/MySourceGenPlugin/Plugins/MySourceGenPrebuildPlugin/plugin.swift

@@ -1,5 +1,11 @@
 import PackagePlugin
 
+#if os(Android)
+let touchExe = "/system/bin/touch"
+#else
+let touchExe = "/usr/bin/touch"
+#endif
+
 @main
 struct MyPlugin: BuildToolPlugin {
 
@@ -15,7 +21,7 @@ struct MyPlugin: BuildToolPlugin {
                 displayName:
                     "Running prebuild command for target \(target.name)",
                 executable:
-                    Path("/usr/bin/touch"),
+                    Path(touchExe),
                 arguments: 
                     outputPaths.map{ $0.string },
                 outputFilesDirectory:

Fixtures/Miscellaneous/Plugins/MySourceGenPluginUsingURLBasedAPI/Plugins/MySourceGenPrebuildPlugin/plugin.swift

@@ -1,6 +1,12 @@
 import Foundation
 import PackagePlugin
 
+#if os(Android)
+let touchExe = "/system/bin/touch"
+#else
+let touchExe = "/usr/bin/touch"
+#endif
+
 @main
 struct MyPlugin: BuildToolPlugin {
 
@@ -16,7 +22,7 @@ struct MyPlugin: BuildToolPlugin {
                 displayName:
                     "Running prebuild command for target \(target.name)",
                 executable:
-                    URL(fileURLWithPath: "/usr/bin/touch"),
+                    URL(fileURLWithPath: touchExe),
                 arguments: 
                     outputPaths.map{ $0.path },
                 outputFilesDirectory:

Sources/Basics/Cancellator.swift

@@ -15,6 +15,8 @@ import Foundation
 import class TSCBasic.Thread
 #if canImport(WinSDK)
 import WinSDK
+#elseif canImport(Android)
+import Android
 #endif
 
 public typealias CancellationHandler = @Sendable (DispatchTime) throws -> Void

Sources/Basics/Concurrency/AsyncProcess.swift

@@ -14,6 +14,8 @@ import Foundation
 
 #if os(Windows)
 import TSCLibc
+#elseif canImport(Android)
+import Android
 #endif
 
 #if os(Linux)

Sources/Basics/Environment/Environment.swift

@@ -19,8 +19,8 @@ import Musl
 #elseif os(Windows)
 import CRT
 import WinSDK
-#elseif canImport(Bionic)
-import Bionic
+#elseif canImport(Android)
+import Android
 #else
 import Darwin.C
 #endif

Sources/Commands/SwiftRunCommand.swift

@@ -22,6 +22,10 @@ import func TSCBasic.exec
 
 import enum TSCUtility.Diagnostics
 
+#if canImport(Android)
+import Android
+#endif
+
 /// An enumeration of the errors that can be generated by the run tool.
 private enum RunError: Swift.Error {
     /// The package manifest has no executable product.

Sources/Commands/SwiftTestCommand.swift

@@ -42,6 +42,8 @@ import class TSCBasic.Thread
 
 #if os(Windows)
 import WinSDK // for ERROR_NOT_FOUND
+#elseif canImport(Android)
+import Android
 #endif
 
 private enum TestError: Swift.Error {
@@ -1484,7 +1486,7 @@ private extension Basics.Diagnostic {
 /// it duplicates the definition of this constant in its own source. Any changes
 /// to this constant in either package must be mirrored in the other.
 private var EXIT_NO_TESTS_FOUND: CInt {
-#if os(macOS) || os(Linux)
+#if os(macOS) || os(Linux) || canImport(Android)
     EX_UNAVAILABLE
 #elseif os(Windows)
     ERROR_NOT_FOUND

Sources/PackagePlugin/Plugin.swift

@@ -36,6 +36,8 @@ internal func strerror(_ errno: CInt) -> String? {
         return String(decodingCString: baseAddress, as: UTF16.self)
     }
 }
+#elseif canImport(Android)
+import Android
 #endif
 
 //

Sources/PackageRegistryCommand/PackageRegistryCommand+Auth.swift

@@ -63,6 +63,10 @@ private func readpassword(_ prompt: String) throws -> String {
     return password
 }
 #else
+#if canImport(Android)
+import Android
+#endif
+
 private func readpassword(_ prompt: String) throws -> String {
     let password: String
 

Tests/BasicsTests/FileSystem/PathShimTests.swift

@@ -38,7 +38,7 @@ class WalkTests: XCTestCase {
         var expected: [AbsolutePath] = [
             "\(root)/usr",
             "\(root)/bin",
-            "\(root)/xbin",
+            "\(root)/etc",
         ]
         #elseif os(Windows)
         let root = ProcessInfo.processInfo.environment["SystemRoot"]!

Tests/FunctionalTests/PluginTests.swift

@@ -208,13 +208,19 @@ final class PluginTests: XCTestCase {
             try localFileSystem.createDirectory(pluginSourceFile.parentDirectory, recursive: true)
             try localFileSystem.writeFileContents(pluginSourceFile, string: """
             import PackagePlugin
+            #if os(Android)
+            let touchExe = "/system/bin/touch"
+            #else
+            let touchExe = "/usr/bin/touch"
+            #endif
+
             @main
             struct Plugin: BuildToolPlugin {
                 func createBuildCommands(context: PluginContext, target: Target) async throws -> [Command] {
                     return [
                         .buildCommand(
                             displayName: "empty",
-                            executable: .init("/usr/bin/touch"),
+                            executable: .init(touchExe),
                             arguments: [context.pluginWorkDirectory.appending("best.txt")],
                             inputFiles: [],
                             outputFiles: []