Support C ext copying on linux only for now

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/copying/MachOFile.java

@@ -151,7 +151,7 @@ public void write(TruffleFile copy) throws IOException, InterruptedException {
         }
         assert buffer.position() == MachOHeader.SIZE64 + mh.sizeOfCmds;
         for (int i = 0; i < emptySpace; i++) {
-            buffer.put((byte)0);
+            buffer.put((byte) 0);
         }
 
         try (var os = copy.newOutputStream(StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING, StandardOpenOption.WRITE)) {

mx.graalpython/mx_graalpython.py

@@ -407,12 +407,17 @@ def __str__(self):
     configs += [
         TestConfig("junit", vm_args + graalpy_tests + args, True),
         TestConfig("junit", vm_args + graalpy_tests + args, False),
-        # MultiContext cext tests should run by themselves so they aren't influenced by others
-        TestConfig("multi-cext", vm_args + ['org.graalvm.python.embedding.cext.test'] + args + (["--use-graalvm"] if has_compiler else []), True),
         # TCK suite is not compatible with the PythonMxUnittestConfig,
         # so it must have its own run and the useResources config is ignored
         TestConfig("tck", vm_args + ['com.oracle.truffle.tck.tests'] + args, False),
     ]
+    if mx.is_linux():
+        # see GR-60656 and GR-60658 for what's missing in darwin and windows support
+        configs.append(
+            # MultiContext cext tests should run by themselves so they aren't influenced by others
+            TestConfig("multi-cext", vm_args + ['org.graalvm.python.embedding.cext.test'] + args + (["--use-graalvm"] if has_compiler else []), True),
+        )
+
     if '--regex' not in args:
         async_regex = ['--regex', r'com\.oracle\.graal\.python\.test\.integration\.advanced\.AsyncActionThreadingTest']
         configs.append(TestConfig("async", vm_args + ['-Dpython.AutomaticAsyncActions=false', 'com.oracle.graal.python.test', 'org.graalvm.python.embedding.utils.test'] + async_regex + args, True, False))