[cmake] Propagate Cocoa backend frameworks to consumers of static raylib on macOS

Bundled GLFW links '-framework Cocoa/IOKit/QuartzCore' privately, and the
static-install export block removes glfw from the exported dependencies.
As a result the installed CMake package only carried OpenGL.framework,
and linking any consumer of libraylib.a failed with undefined Objective-C
symbols (_objc_retain etc.).

Append the three frameworks to the static install interface when the
bundled GLFW is used, so installed consumers get a complete link line.

src/CMakeLists.txt

@@ -114,6 +114,19 @@ if (NOT BUILD_SHARED_LIBS)
 
     if (NOT glfw3_FOUND)
         list(REMOVE_ITEM raylib_install_private_libs glfw)
+
+        # Bundled GLFW links its Cocoa backend frameworks privately, so they
+        # must be propagated to consumers of the static library, whose final
+        # link line would otherwise miss them.
+        if (APPLE)
+            find_library(COCOA_FRAMEWORK Cocoa)
+            find_library(IOKIT_FRAMEWORK IOKit)
+            find_library(QUARTZCORE_FRAMEWORK QuartzCore)
+            list(APPEND raylib_install_private_libs
+                ${COCOA_FRAMEWORK}
+                ${IOKIT_FRAMEWORK}
+                ${QUARTZCORE_FRAMEWORK})
+        endif ()
     endif()
 
     foreach(lib IN LISTS raylib_install_private_libs)