Revert the bootstrap changes to copy the SwiftPM-built universal PackageDescription and PackagePlugin libraries

This goes back to copying the CMake-built libraries instead of the SwiftPM-built ones.  This means that they will be thin on macOS, built only for the architecture of the host on which they were built.  This is temporary until the Xcode that is used on the builders is new enough to have the XCBuild support needed for emitting Swift module interfaces.

Author: abertelrud

Utilities/bootstrap

@@ -396,13 +396,42 @@ def install_swiftpm(prefix, args):
         dest = os.path.join(prefix, "libexec", "swift", "pm")
         install_binary(args, "swiftpm-xctest-helper", dest)
 
-    # Install the PackageDescription library and associated modules.
-    dest = os.path.join(prefix, "lib", "swift", "pm", "ManifestAPI")
-    install_dylib(args, "PackageDescription", dest, ["PackageDescription"])
+    # Install PackageDescription runtime libraries.
+    runtime_lib_dest = os.path.join(prefix, "lib", "swift", "pm")
+    runtime_lib_src = os.path.join(args.bootstrap_dir, "pm")
 
-    # Install the PackagePlugin library and associated modules.
-    dest = os.path.join(prefix, "lib", "swift", "pm", "PluginAPI")
-    install_dylib(args, "PackagePlugin", dest, ["PackagePlugin"])
+    files_to_install = ["libPackageDescription" + g_shared_lib_suffix]
+    if platform.system() == 'Darwin':
+        files_to_install.append("PackageDescription.swiftinterface")
+    else:
+        files_to_install.append("PackageDescription.swiftmodule")
+    files_to_install.append("PackageDescription.swiftdoc")
+
+    for file in files_to_install:
+        src = os.path.join(runtime_lib_src, "ManifestAPI", file)
+        dest = os.path.join(runtime_lib_dest, "ManifestAPI", file)
+        mkdir_p(os.path.dirname(dest))
+
+        note("Installing %s to %s" % (src, dest))
+
+        file_util.copy_file(src, dest, update=1)
+
+    # Install PackagePlugin runtime libraries.
+    files_to_install = ["libPackagePlugin" + g_shared_lib_suffix]
+    if platform.system() == 'Darwin':
+        files_to_install.append("PackagePlugin.swiftinterface")
+    else:
+        files_to_install.append("PackagePlugin.swiftmodule")
+    files_to_install.append("PackagePlugin.swiftdoc")
+
+    for file in files_to_install:
+        src = os.path.join(runtime_lib_src, "PluginAPI", file)
+        dest = os.path.join(runtime_lib_dest, "PluginAPI", file)
+        mkdir_p(os.path.dirname(dest))
+
+        note("Installing %s to %s" % (src, dest))
+
+        file_util.copy_file(src, dest, update=1)
 
 
 # Helper function that installs a dynamic library and a set of modules to a particular directory.