wasmswiftsdk.py: consistently apply build_runtime_with_host_compiler

Following up on swiftlang#83134 swiftlang#82949 swiftlang#82946 swiftlang#82944

Author: MaxDesiatov

utils/swift_build_support/swift_build_support/products/wasmswiftsdk.py

@@ -130,7 +130,7 @@ def _build_libxml2(self, swift_host_triple, has_pthread, wasi_sysroot):
         libxml2.cmake_options.define('HAVE_PTHREAD_H', cmake_thread_enabled)
 
         libxml2.build_with_cmake([], self.args.build_variant, [],
-                                 prefer_native_toolchain=True,
+                                 prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
                                  ignore_extra_cmake_options=True)
         with shell.pushd(libxml2.build_dir):
             shell.call([self.toolchain.cmake, '--install', '.', '--prefix', '/', '--component', 'development'],
@@ -159,7 +159,7 @@ def _build_foundation(self, swift_host_triple, has_pthread, wasi_sysroot):
         foundation.cmake_options.define('LIBXML2_LIBRARY', os.path.join(wasi_sysroot, 'lib'))
 
         foundation.build_with_cmake([], self.args.build_variant, [],
-                                    prefer_native_toolchain=True,
+                                    prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
                                     ignore_extra_cmake_options=True)
 
         dest_dir = self._target_package_path(swift_host_triple)
@@ -186,7 +186,7 @@ def _build_swift_testing(self, swift_host_triple, has_pthread, wasi_sysroot):
         swift_testing.cmake_options.define('SwiftTesting_MACRO', 'NO')
 
         swift_testing.build_with_cmake([], self.args.build_variant, [],
-                                       prefer_native_toolchain=True,
+                                       prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
                                        ignore_extra_cmake_options=True)
         dest_dir = self._target_package_path(swift_host_triple)
         with shell.pushd(swift_testing.build_dir):
@@ -206,7 +206,7 @@ def _build_xctest(self, swift_host_triple, has_pthread, wasi_sysroot):
         xctest.cmake_options.define('BUILD_SHARED_LIBS', 'FALSE')
 
         xctest.build_with_cmake([], self.args.build_variant, [],
-                                prefer_native_toolchain=True,
+                                prefer_native_toolchain=not self.args.build_runtime_with_host_compiler,
                                 ignore_extra_cmake_options=True)
         dest_dir = self._target_package_path(swift_host_triple)
         with shell.pushd(xctest.build_dir):