#3705: Command-line arguments were not correctly decoded when the
terminal does not use UTF8.

Now the code propagates the unicode string as far as possible, and avoids
the conversion to char* which implicitely uses utf-8.

Reviewed by Benjamin.
diff --git a/Modules/main.c b/Modules/main.c
index 6fdc33a..78913ee 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -287,7 +287,7 @@
 {
 	int c;
 	int sts;
-	char *command = NULL;
+	wchar_t *command = NULL;
 	wchar_t *filename = NULL;
 	wchar_t *module = NULL;
 	FILE *fp = stdin;
@@ -299,7 +299,6 @@
 	int version = 0;
 	int saw_unbuffered_flag = 0;
 	PyCompilerFlags cf;
-	char *oldloc;
 
 	cf.cf_flags = 0;
 
@@ -310,30 +309,19 @@
 
 	while ((c = _PyOS_GetOpt(argc, argv, PROGRAM_OPTS)) != EOF) {
 		if (c == 'c') {
-			size_t r1, r2;
-			oldloc = setlocale(LC_ALL, NULL);
-			setlocale(LC_ALL, "");
-			r1 = wcslen(_PyOS_optarg);
-			r2 = wcstombs(NULL, _PyOS_optarg, r1);
-			if (r2 == (size_t) -1)
-				Py_FatalError(
-				   "cannot convert character encoding of -c argument");
-			if (r2 > r1)
-				r1 = r2;
-			r1 += 2;
+			size_t len;
 			/* -c is the last option; following arguments
 			   that look like options are left for the
 			   command to interpret. */
-			command = (char *)malloc(r1);
+
+			len = wcslen(_PyOS_optarg) + 1 + 1;
+			command = (wchar_t *)malloc(sizeof(wchar_t) * len);
 			if (command == NULL)
 				Py_FatalError(
 				   "not enough memory to copy -c argument");
-			r2 = wcstombs(command, _PyOS_optarg, r1);
-			if (r2 > r1-1)
-				Py_FatalError(
-				    "not enough memory to copy -c argument");
-			strcat(command, "\n");
-			setlocale(LC_ALL, oldloc);
+			wcscpy(command, _PyOS_optarg);
+			command[len - 2] = '\n';
+			command[len - 1] = 0;
 			break;
 		}
 
@@ -543,8 +531,18 @@
 	}
 
 	if (command) {
-		sts = PyRun_SimpleStringFlags(command, &cf) != 0;
+		PyObject *commandObj = PyUnicode_FromWideChar(
+		    command, wcslen(command));
 		free(command);
+		if (commandObj != NULL) {
+			sts = PyRun_SimpleStringFlags(
+				_PyUnicode_AsString(commandObj), &cf) != 0;
+		}
+		else {
+			PyErr_Print();
+			sts = 1;
+		}
+		Py_DECREF(commandObj);
 	} else if (module) {
 		sts = RunModule(module, 1);
 	}