When I try to compile this module

```
(module $empty)
```

with
```
wasm2wat --version

wat2wasm empty.wat
wasm2c empty.wasm -o empty
```
I get the following error message:
```
1.0.35
terminate called after throwing an instance of 'std::out_of_range'
  what():  basic_string_view::substr: __pos (which is 18446744073709551615) > __size (which is 5)
./do.sh: line 4: 392733 Aborted                 (core dumped) wasm2c empty.wasm -o empty
```
wasm2c compiling minimal example issues
This is a GitHub Issue
repo:wabt
owner:WebAssembly
Title : wasm2c compiling minimal example issues
Issue date:

--- start body ---
When I try to compile this module

```
(module $empty)
```

with
```
wasm2wat --version

wat2wasm empty.wat
wasm2c empty.wasm -o empty
```
I get the following error message:
```
1.0.35
terminate called after throwing an instance of 'std::out_of_range'
  what():  basic_string_view::substr: __pos (which is 18446744073709551615) > __size (which is 5)
./do.sh: line 4: 392733 Aborted                 (core dumped) wasm2c empty.wasm -o empty
```
--- end body ---
