macOS builds use homebrew rpath instead of bundled libraries.

#### Steps to reproduce
1. Have a Baldur's Gate 1 installation ready to go -- in my case it's a Windows install of base game + TOTSC done via Whisky
2. Download and extract a macOS ARM gemrb build
3. Open GemRB.app
4. Select Baldur Gate 1 (original ed. as per no EE support mention) game directory as Game Path
3a. (Toggle Logging option on)
5. Click on Launch
6. Get the undescriptive error message both as a popup and in GemRB.log:
```
[Core/]: Initializing Video Driver...
[Cocoa Wrapper/FATAL]: Unable to initialize core: No Video Driver Available.. Terminating.
```

#### Expected behavior
Information on whether I'm missing any dependencies; info. on how/where to set the SDL path / version.

#### Screenshots

GemRB version (check as many as you know apply)
- [ x ] master as of this issue
- [ x ] 0.9.2

(I have tried two builds linked on the [gemrb website](https://gemrb.org/Install.html):
- https://sourceforge.net/projects/gemrb/files/Buildbot%20Binaries/Apple/ARM64/gemrb-2023-07-13-7817597b.zip/download
- https://sourceforge.net/projects/gemrb/files/Releases/0.9.2/gemrb-macos-arm64-v0.9.2.zip/download
)

Video Driver (check as many as you know apply)
- [ ] SDL1.2
- [ ] SDL2 built with `USE_OPENGL_BACKEND`
- [ ] SDL2 without `USE_OPENGL_BACKEND`
I do not know, nor can I see a way to check without rebuilding the application myself. I did have sdl2 package installed with home-brew, adding sdl2-gfx and sdl2-image didn't help.
```
~% brew list | grep sdl
sdl2
sdl2_gfx
sdl2_image
~% brew list sdl2
/opt/homebrew/Cellar/sdl2/2.28.1/bin/sdl2-config
/opt/homebrew/Cellar/sdl2/2.28.1/include/SDL2/ (78 files)
/opt/homebrew/Cellar/sdl2/2.28.1/lib/libSDL2-2.0.0.dylib
/opt/homebrew/Cellar/sdl2/2.28.1/lib/cmake/ (2 files)
/opt/homebrew/Cellar/sdl2/2.28.1/lib/pkgconfig/sdl2.pc
/opt/homebrew/Cellar/sdl2/2.28.1/lib/ (4 other files)
/opt/homebrew/Cellar/sdl2/2.28.1/share/aclocal/sdl2.m4
~% which sdl2-config
/opt/homebrew/bin/sdl2-config
```

Start by reproducing the failure with the macOS ARM GemRB.app build and inspect GemRB.log alongside the app's linked libraries and rpath. Check whether the bundled SDL dependencies are used instead of the Homebrew installation; done means the app launches without requiring Homebrew SDL libraries and reports a useful dependency error when they are unavailable.

Written by the indexing model from the issue text.