[Question] `getHeader` - how to use it with a system installed library
It is not clear to me how to use `getHeader` when I want to use existing headers in my system. I have a library called OpenCascade. This is a C++ library that I'd like to test with `c2nImport`. 

The headers are under: `/usr/include/opencascade`. I have tried:
```
getHeader("Geom2d_CartesianPoint.hxx")
```
and:
```
getHeader("opencascade/Geom2d_CartesianPoint.hxx")
```
But I get errors like:
```
stack trace: (most recent call last)
/home/jose/.nimble/pkgs/nimterop-#head/nimterop/build/getheader.nim(482, 23)
/home/jose/.nimble/pkgs/nimterop-#head/nimterop/build/getheader.nim(235, 11) buildLibrary
/home/jose/.choosenim/toolchains/nim-1.2.6/lib/system/assertions.nim(29, 26) failedAssertImpl
/home/jose/.choosenim/toolchains/nim-1.2.6/lib/system/assertions.nim(22, 11) raiseAssert
/home/jose/.choosenim/toolchains/nim-1.2.6/lib/system/fatal.nim(49, 5) sysFatal
/home/jose/src/3d/occt/occt_wrapper.nim(28, 10) template/generic instantiation of `getHeader` from here
/home/jose/.choosenim/toolchains/nim-1.2.6/lib/system/fatal.nim(49, 5) Error: unhandled exception: /home/jose/.nimble/pkgs/nimterop-#head/nimterop/build/getheader.nim(235, 12) `buildStatus.built` 
Build configuration failed - No build files found in 
```

How should I use it?