docs: update README.md

Edit the "Running the Game" section to include macOS-specific information regarding dynamic linking of the fmod library.

Author: traunts

README.md

@@ -101,9 +101,14 @@ If you want to change the buildtype afterwards, you can use `meson configure --b
 
    `cd $DATA_REPOSITORY; ln -s ../Cortex-Command-Community-Project-Source/build/CortexCommand . `
 
-2. Copy all `libfmod` files from `external/lib/linux/x86_64` into the **Data Repository**.
+2. 
+   - #### Linux:
+      Copy (link) all `libfmod` files from `external/lib/linux/x86_64` into the **Data Repository**.
 
-   `cd $DATA_REPOSITORY; ln -s ../Cortex-Command-Community-Project-Source/external/lib/linux/x86_64/libfmod.so* .`
+      `cd $DATA_REPOSITORY; ln -s ../Cortex-Command-Community-Project-Source/external/lib/linux/x86_64/libfmod.so* .`
+
+   - #### macOS
+      macOS builds automatically resolve the relative path from `build/` where the executable exists to `external/lib/macos/`. If the executable is being launched via the symlink from Step 1 then this step is not required. 
 
 4. Run `./CortexCommand` or `./CortexCommand_debug` in the **Data Repository**.