FIX: to-real-file not working correctly with Unicode paths on Posix

resolves: Oldes/Rebol-issues#2599

Author: Oldes

src/core/n-io.c

@@ -504,7 +504,18 @@ static REBSER *Read_All_File(char *fname)
 	if (!tmp) return R_NONE;
 
 	// Convert OS native wide string back to Rebol file type
-	new = To_REBOL_Path(tmp, 0, OS_WIDE, FALSE);
+	if (OS_WIDE) {
+		new = To_REBOL_Path(tmp, 0, OS_WIDE, FALSE);
+	} else {
+		REBLEN len = LEN_BYTES(tmp);
+		if (Is_Not_ASCII(tmp, len)) {
+			// Result from the native call contains Unicode chars...
+			new = Decode_UTF_String(tmp, len, 8, FALSE, FALSE);
+			new = To_REBOL_Path(SERIES_DATA(new), SERIES_TAIL(new), -1, FALSE);
+		} else {
+			new = To_REBOL_Path(tmp, len, 0, FALSE);
+		}
+	}
 	if (!new) return R_NONE;
 
 	Set_Series(REB_FILE, D_RET, new);

src/tests/units/file-test.r3

@@ -96,6 +96,19 @@ if find [Linux macOS] system/platform [
 
 
 ===start-group=== "to-real-file"
+--test-- "On file"
+	write file: %jesterka ""
+	full: join what-dir file
+	--assert equal? full to-real-file file
+	--assert equal? full to-real-file join %./ file
+	delete file
+--test-- "On file with Unicode chars"
+	;@@ https://github.com/Oldes/Rebol-issues/issues/2599
+	write file: %jěštěrka ""
+	full: join what-dir file
+	--assert equal? full to-real-file file
+	--assert equal? full to-real-file join %./ file
+	delete file
 --test-- "On directory"
 	;@@ https://github.com/Oldes/Rebol-issues/issues/2600
 	--assert equal? what-dir to-real-file %.