[build] Fix native GLFW build

Fixes an undefined reference to `glfwGetWindowAttrib` when building with
GLFW support enabled.

src/wsi/glfw/wsi_platform_glfw_funcs.h

@@ -5,6 +5,7 @@ GLFW_PROC(GLFWmonitor*, glfwGetPrimaryMonitor, (void))
 GLFW_PROC(const char**, glfwGetRequiredInstanceExtensions, (uint32_t*))
 GLFW_PROC(const GLFWvidmode*, glfwGetVideoMode, (GLFWmonitor*))
 GLFW_PROC(const GLFWvidmode*, glfwGetVideoModes, (GLFWmonitor*, int*))
+GLFW_PROC(int, glfwGetWindowAttrib, (GLFWwindow*, int))
 GLFW_PROC(void, glfwGetWindowSize, (GLFWwindow*, int*, int*))
 GLFW_PROC(void, glfwSetWindowMonitor, (GLFWwindow*, GLFWmonitor*, int, int, int, int, int))
 GLFW_PROC(void, glfwSetWindowSize, (GLFWwindow*, int, int))