fix for 3307 (windows launcher rejects filenames with utf8 chars)

[philwalk]

This PR modifies generate-native-image.sh to generate scala-cli.exe with code page set to 65001 if running in Windows:

• save current code page
• set code page to 65001
• generate scala-cli.exe
• restore the code page atexit

Using a test script named /opt/ue/jsrc/løp.sc:

#!/usr/bin/env -S scala-cli shebang
printf("Hello %s\n", scriptPath)
printf("Hello %s\n", sys.props("scala.sources"))
printf("Hello %s\n", sys.props("scala.source.names"))

and with the PATH set to use the generated scala-cli.exe:

PATH="out/cli/3.3.7/base-image/nativeImage.dest:$PATH"

Manual verification that the bug and the fix depend on the code page set during GraalVM compile.

verify the bug

create a buggy scala-cli.exe by running generated-native-image.sh temporarily modified to set code page 437
Verify that the bug manifests itself when attempting to execute the script:

# /opt/ue/jsrc/løp.sc
[error]  File not found: C:\opt\ue\jsrc\løp.sc

Verify the fix

create fixed scala-cli.exe by running generated-native-image.sh as proposed in this PR (set code page 65001)
Verify that the bug is fixed:

# /opt/ue/jsrc/løp.sc
Hello /opt/ue/jsrc/løp.sc
Hello C:/opt/ue/jsrc/løp.sc
Hello løp.sc

[philwalk]

The error messages for the failing tests are the result of having Windows code page 437 active.
I assume that (at least as of jdk17) we need to set the code page to 65001 in Windows before running this test.

The failure is that a script named TestÅÄÖåäö.sc with contents:

object TestÅÄÖåäö {
  def main(args: Array[String]): Unit = {
    println("Hello from TestÅÄÖåäö")
  }
}

failed with this error message:

[950] Error: Could not find or load main class TestÅÄÖåäö
[950] Caused by: java.lang.ClassNotFoundException: TestÅÄÖåäö

# ./mill integration.test.native 'scala.cli.integration.RunTestsDefault.UTF-8'

[949] Produced artifacts:
[949]  C:\Users\philwalk\workspace\scala-cli-3307\out\cli\3.3.7\base-image\nativeImage.dest\scala-cli.build_artifacts.txt (txt)
[949]  C:\Users\philwalk\workspace\scala-cli-3307\out\cli\3.3.7\base-image\nativeImage.dest\scala-cli.exe (executable)
[949] ========================================================================================================================
[949] Finished generating 'scala-cli' in 3m 49s.
[950/950] integration.test.native
[950] >==== Running 'UTF-8' from RunTestDefinitions
[950] Running warmup testà
[950] Compiling project (Scala 3.7.3, JVM (17))
[950] Compiled project (Scala 3.7.3, JVM (17))
[950] Done running warmup test.
[950] Compiling project (Scala 3.7.3, JVM (17))
[950] Compiled project (Scala 3.7.3, JVM (17))
[950] Error: Could not find or load main class TestÅÄÖåäö
[950] Caused by: java.lang.ClassNotFoundException: TestÅÄÖåäö
[950] X==== Finishing 'UTF-8' from RunTestDefinitions
[950] scala.cli.integration.RunTestsDefault:
[950] ==> X scala.cli.integration.RunTestsDefault.UTF-8  2.017s os.SubprocessException: Result of C:\Users\philwalk\workspace\scala-cli-3307\out\cli\3.3.7\base-image\nativeImage.dest\scala-cli.exeà: 1
[950]
[950]     at os.proc.call(ProcessOps.scala:232)
[950]     at scala.cli.integration.RunTestDefinitions.$anonfun$new$117(RunTestDefinitions.scala:1080)
[950]     at scala.cli.integration.RunTestDefinitions.$anonfun$new$117$adapted(RunTestDefinitions.scala:1072)
[950]     at scala.cli.integration.TestInputs.$anonfun$fromRoot$1(TestInputs.scala:35)
[950]     at scala.cli.integration.TestInputs$.scala$cli$integration$TestInputs$$withTmpDir(TestInputs.scala:95)
[950]     at scala.cli.integration.TestInputs.fromRoot(TestInputs.scala:33)
[950]     at scala.cli.integration.RunTestDefinitions.$anonfun$new$116(RunTestDefinitions.scala:1072)
[950]     at scala.cli.integration.WithWarmUpScalaCliSuite.$anonfun$test$1(WithWarmUpScalaCliSuite.scala:34)
[950]     at scala.cli.integration.WithWarmUpScalaCliSuite.$anonfun$test$2(WithWarmUpScalaCliSuite.scala:37)
[950/950, 1 failed] ============================== integration.test.native scala.cli.integration.RunTestsDefault.UTF-8 ============================== 265s
1 tasks failed
integration.test.native 1 tests failed:
  scala.cli.integration.RunTestsDefault.UTF-8 scala.cli.integration.RunTestsDefault.UTF-8
philwalk@d5 MSYS ~/workspace/scala-cli-3307

[Gedochao]

I assume that (at least as of jdk17) we need to set the code page to 65001 in Windows before running this test.

Do you maybe know how to do it? Can't say I'm familiar with code pages in Windows, myself.
The fix looks good otherwise, we just need to get the tests fixed.