Cocoa: Add fully dynamic loading of Vulkan loader

From upstream: 7da87aaae7.

glfw/cocoa_init.m

@@ -529,6 +529,32 @@ static GLFWapplicationwillfinishlaunchingfun finish_launching_callback = NULL;
 @end
 
 
+//////////////////////////////////////////////////////////////////////////
+//////                       GLFW internal API                      //////
+//////////////////////////////////////////////////////////////////////////
+
+void* _glfwLoadLocalVulkanLoaderNS(void)
+{
+    CFBundleRef bundle = CFBundleGetMainBundle();
+    if (!bundle)
+        return NULL;
+
+    CFURLRef url =
+        CFBundleCopyAuxiliaryExecutableURL(bundle, CFSTR("libvulkan.1.dylib"));
+    if (!url)
+        return NULL;
+
+    char path[PATH_MAX];
+    void* handle = NULL;
+
+    if (CFURLGetFileSystemRepresentation(url, true, (UInt8*) path, sizeof(path) - 1))
+        handle = _glfw_dlopen(path);
+
+    CFRelease(url);
+    return handle;
+}
+
+
 //////////////////////////////////////////////////////////////////////////
 //////                       GLFW platform API                      //////
 //////////////////////////////////////////////////////////////////////////

glfw/cocoa_platform.h

@@ -239,6 +239,8 @@ void _glfwRestoreVideoModeNS(_GLFWmonitor* monitor);
 
 float _glfwTransformYNS(float y);
 
+void* _glfwLoadLocalVulkanLoaderNS(void);
+
 void _glfwClearDisplayLinks(void);
 void _glfwRestartDisplayLinks(void);
 void _glfwDispatchTickCallback(void);

glfw/vulkan.c

@@ -57,6 +57,8 @@ bool _glfwInitVulkan(int mode)
     _glfw.vk.handle = _glfw_dlopen("vulkan-1.dll");
 #elif defined(_GLFW_COCOA)
     _glfw.vk.handle = _glfw_dlopen("libvulkan.1.dylib");
+    if (!_glfw.vk.handle)
+        _glfw.vk.handle = _glfwLoadLocalVulkanLoaderNS();
 #else
     _glfw.vk.handle = _glfw_dlopen("libvulkan.so.1");
 #endif