Segfault in vkInit calling vkGetProcAddress
**Note: for support questions, please use stackoverflow or irc**. This
repository's issues are reserved for feature requests and bug reports.


* **Do you want to request a *feature* or report a *bug*?**
Bug report


* **What is the current behavior?**
segfaults


* **If the current behavior is a bug, please provide the steps to reproduce and
if possible a minimal demo of the problem**
```
import nimgl/vulkan
discard vkInit()
```

* **Please tell us about your environment:**
  
  - Version: 1.0.0 
  - OS:  Linux
  - Bindings: Vulkan 
  - Backend: C 


* **Other information** (e.g. detailed explanation, stacktraces, related issues,
suggestions how to fix, links for us to have context, eg. stackoverflow,
docs.gl, documentation etc)


```
/home/kieran/.nimble/pkgs/nimgl-1.0.0/nimgl/vulkan.nim(9265) vkInit
/home/kieran/.nimble/pkgs/nimgl-1.0.0/nimgl/vulkan.nim(8694) vkLoad1_0
/home/kieran/.nimble/pkgs/nimgl-1.0.0/nimgl/vulkan.nim(29) :anonymous
SIGSEGV: Illegal storage access. (Attempt to read from nil?)
```

* **Workaround**
deleting the line that causes the crash `result = vkGetProcAddress(procName)` leads to a fallback loading which works correctly.