We have an issue in dwg_find_color_index(), which is not working.

The problem is with:
```
BITCODE_BL rgb = 0xff0000;
Dwg_RGB_Palette pal;
pal.r = rgb & 0xff0000;
```
where BITCODE_BL is uint32_t and pal.r is unsigned char and conversion isn't working.
Issue in dwg_find_color_index()
This is a GitHub Issue
repo:libredwg
owner:LibreDWG
Title : Issue in dwg_find_color_index()
Issue date:

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We have an issue in dwg_find_color_index(), which is not working.

The problem is with:
```
BITCODE_BL rgb = 0xff0000;
Dwg_RGB_Palette pal;
pal.r = rgb & 0xff0000;
```
where BITCODE_BL is uint32_t and pal.r is unsigned char and conversion isn't working.
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