In macOS, system libraries are defined as "frameworks". A framework is usually a folder like:

/System/Library/Frameworks/OpenGL.framework/Versions/Current/OpenGL

There are two peculiarities here:

1. there is no shared library in this location. E.g. the above path doesn't contain any `libGL.dylib`. Instead, `dlopen` expects the framework folder to be passed as argument if OpenGL is to be loaded.

2. there are no include files. Moreover, while include files can be found in Xcode-specific folders, such as:

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/OpenGL.framework/Headers

Such header files are in the "wrong location". That is, a dependent header will contain an include such as this:

```
#include <OpenGL/gl.h>
```

But there is no path matchinhg "*OpenGL/gl.h" installed on the system. Instead, the name before the "/" is interpreted as a "framework name", and the subsequent path is intended to be relative to the framework's `Headers` folder.

On macOS, both issues are automatically addressed by providing the `-framework` option to the native compiler. E.g.

```
-framework OpenGL
```

Without explicit support for frameworks and framework locations (-f and -F), it is not possible to extract headers that depend on system libraries in macOS. Instead, users need to fetch replicas of such libraries via homebrew, which are not guaranteed to match the version installed in their systems.