build-script: Add --install-wasmkit option

This allows skipping the installation step and only building WasmKit, which is consistent to how other products are handled by `build-script`, where they have separate `--install` options. Existing behavior is preserved, where passing `--wasmkit` alone will install it, but now `--wasmkit --install-wasmkit false` will skip its installation step.

Author: MaxDesiatov

utils/build_swift/build_swift/driver_arguments.py

@@ -292,6 +292,12 @@ def _apply_default_arguments(args):
         args.test_xros_host = False
         args.test_android_host = False
 
+    # Install WasmKit if it's built
+    # (ideally, should not be installed by default, same as other products, but
+    # historically `--wasmkit` implied installation)
+    if args.build_wasmkit and args.install_wasmkit is None:
+        args.install_wasmkit = True
+
 
 def create_argument_parser():
     """Return a configured argument parser."""
@@ -823,11 +829,18 @@ def create_argument_parser():
     option(['--build-minimal-stdlib'], toggle_true('build_minimalstdlib'),
            help='build the \'minimal\' freestanding stdlib variant into a '
                 'separate build directory ')
+
+    # Wasm options
+
     option(['--build-wasm-stdlib'], toggle_true('build_wasmstdlib'),
            help='build the stdlib for WebAssembly target into a'
                 'separate build directory ')
     option(['--wasmkit'], toggle_true('build_wasmkit'),
            help='build WasmKit')
+    option(['--install-wasmkit'], toggle_true('install_wasmkit'),
+           help='install SourceKitLSP')
+
+    # Swift Testing options
 
     option('--swift-testing', toggle_true('build_swift_testing'),
            help='build Swift Testing')

utils/swift_build_support/swift_build_support/products/wasmkit.py

@@ -47,8 +47,7 @@ def should_test(self, host_target):
         return False
 
     def should_install(self, host_target):
-        # Currently, it's only used for testing stdlib.
-        return True
+        return self.args.install_wasmkit
 
     def install(self, host_target):
         """
@@ -61,10 +60,10 @@ def install(self, host_target):
 
     def build(self, host_target):
         bin_path = run_swift_build(host_target, self, 'wasmkit-cli')
-        print("Built wasmkit-cli at: " + bin_path)
+        print("Built wasmkit-cli at: " + bin_path, flush=True)
         # Copy the built binary to ./bin
         dest_bin_path = self.__class__.cli_file_path(self.build_dir)
-        print("Copying wasmkit-cli to: " + dest_bin_path)
+        print("Copying wasmkit-cli to: " + dest_bin_path, flush=True)
         os.makedirs(os.path.dirname(dest_bin_path), exist_ok=True)
         shutil.copy(bin_path, dest_bin_path)