For testing on Android

Package.swift

@@ -1,3 +1,23 @@
+// swift-tools-version:4.0
+//
+// To build with auto-linking of the .swiftmodule use:
+// $ swift build -Xswiftc -module-link-name -Xswiftc XCTest
+//
+
 import PackageDescription
 
-let package = Package(name: "XCTest")
+let package = Package(
+    name: "XCTest",
+    products: [
+        .library(
+            name: "XCTest",
+            type: .dynamic,
+            targets: ["XCTest"]
+        )
+    ],
+    dependencies: [
+    ],
+    targets: [
+        .target(name: "XCTest", dependencies: [], path: "Sources"),
+    ]
+)

Sources/XCTest/Private/PrintObserver.swift

@@ -59,7 +59,9 @@ internal class PrintObserver: XCTestObservation {
 
     fileprivate func printAndFlush(_ message: String) {
         print(message)
+        #if !os(Android)
         fflush(stdout)
+        #endif
     }
 
     private func formatTimeInterval(_ timeInterval: TimeInterval) -> String {

build_script.py

@@ -200,13 +200,14 @@ def build(args):
                 libdispatch_args=libdispatch_args,
                 source_paths=" ".join(sourcePaths)))
         run("{swiftc} -emit-library {build_dir}/XCTest.o "
-            "-L {foundation_build_dir} -lswiftGlibc -lswiftCore -lFoundation -lm "
+            "-L {dispatch_build_dir} -L {foundation_build_dir} -lswiftGlibc -lswiftCore -lFoundation -lm "
             # We embed an rpath of `$ORIGIN` to ensure other referenced
             # libraries (like `Foundation`) can be found solely via XCTest.
             "-Xlinker -rpath=\\$ORIGIN "
             "-o {build_dir}/libXCTest.so".format(
                 swiftc=swiftc,
                 build_dir=build_dir,
+                dispatch_build_dir=os.path.join(args.libdispatch_build_dir, 'src', '.libs'),
                 foundation_build_dir=foundation_build_dir))
 
         # Build the static library.