dlang opengl / gl / glu /glut library.

[Alain De Vos]

First opengl test.
Link library.
```
import std.stdio;
import bindc.opengl;

void main()
{
	writeln("Edit source/app.d to start your project.");
}
x: /home/x/Src/languages/dlang/opengl >
```

dub.json:
```

	"authors": [
		"x"
	],
	"copyright": "Copyright © 2021, x",
	"dependencies": {
		"bindbc-opengl": "~>0.16.0",
	},
	"description": "A minimal D application.",
	"license": "proprietary",
	"name": "opengl"
}

```

dub build
```
dub build
Performing "debug" build using /usr/local/bin/ldc2 for x86_64.
bindbc-loader 0.3.2: target for configuration "noBC" is up to 
date.
bindbc-opengl 0.16.0: target for configuration "dynamic" is up to 
date.
opengl ~master: building configuration "application"...
source/app.d(2,8): Error: module opengl is in file 
'bindc/opengl.d' which cannot be read
import path[0] = source/
import path[1] = 
/home/x/.dub/packages/bindbc-opengl-0.16.0/bindbc-opengl/source/
import path[2] = 
/home/x/.dub/packages/bindbc-loader-0.3.2/bindbc-loader/source/
import path[3] = /usr/local/include/d
/usr/local/bin/ldc2 failed with exit code 1.

```