[jnigen] Use utf-8 for standard error and standard out encoding

pkgs/jni/CHANGELOG.md

@@ -1,6 +1,7 @@
-## 0.9.1-wip
+## 0.9.1
 
-- Fix compilation on macOS for consumers that don't use JNI on macOS (which is still not supported) ([#1122](https://github.com/dart-lang/native/pull/1122)). 
+- Fixed compilation on macOS for consumers that don't use JNI on macOS (which is
+  still not supported) ([#1122](https://github.com/dart-lang/native/pull/1122)).
 
 ## 0.9.0
 

pkgs/jnigen/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.9.1
+
+- Fixed a bug in summarizer where standard output would use the default encoding
+  of the operating system and therefore breaking the UTF-8 decoding for some
+  locales.
+
 ## 0.9.0
 
 - **Breaking Change** ([#660](https://github.com/dart-lang/native/issues/660)):

pkgs/jnigen/lib/src/summary/summary.dart

@@ -88,8 +88,12 @@ class SummarizerCommand {
     args.addAll(extraArgs);
     args.addAll(classes);
     log.info('execute $exec ${args.join(' ')}');
-    final proc = await Process.start(exec, args,
-        workingDirectory: workingDirectory?.toFilePath() ?? '.');
+    final proc = await Process.start(
+      exec,
+      args,
+      workingDirectory: workingDirectory?.toFilePath() ?? '.',
+      environment: {'JAVA_TOOL_OPTIONS': '-Dfile.encoding=UTF8'},
+    );
     return proc;
   }
 }