There is call:
```
encode_preR13_section (SECTION_BLOCK, dat, dwg);
```
But in ```encode_preR13_section()``` is the possibility of returned error.

I am proposing to change to:
```
error |= encode_preR13_section (SECTION_BLOCK, dat, dwg);
```
in dwg_encode are not properly handled errors
This is a GitHub Issue
repo:libredwg
owner:LibreDWG
Title : in dwg_encode are not properly handled errors
Issue date:

--- start body ---
There is call:
```
encode_preR13_section (SECTION_BLOCK, dat, dwg);
```
But in ```encode_preR13_section()``` is the possibility of returned error.

I am proposing to change to:
```
error |= encode_preR13_section (SECTION_BLOCK, dat, dwg);
```
--- end body ---
