improve WGPU / GLFW / Wayland story by weak linking and adjusting docs

vendor/glfw/bindings/bindings.odin

@@ -197,7 +197,12 @@ foreign glfw {
 
 	SetErrorCallback :: proc(cbfun: ErrorProc) -> ErrorProc ---
 
+	// Functions added in 3.4, Linux links against system glfw so we define these as weak to be able
+	// to check at runtime if they are available.
+
+	@(linkage="weak")
 	GetPlatform       :: proc() -> c.int ---
+	@(linkage="weak")
 	PlatformSupported :: proc(platform: c.int) -> b32 ---
 }
 

vendor/glfw/native_linux.odin

@@ -13,7 +13,13 @@ foreign {
 	SetX11SelectionString :: proc(string:  cstring) ---
 	GetX11SelectionString :: proc() -> cstring ---
 
+	// Functions added in 3.4, Linux links against system glfw so we define these as weak to be able
+	// to check at runtime if they are available.
+
+	@(linkage="weak")
 	GetWaylandDisplay :: proc()                       -> rawptr /* struct wl_display* */ ---
+	@(linkage="weak")
 	GetWaylandWindow  :: proc(window:  WindowHandle)  -> rawptr /* struct wl_surface* */ ---
+	@(linkage="weak")
 	GetWaylandMonitor :: proc(monitor: MonitorHandle) -> rawptr /* struct wl_output*  */ ---
 }

vendor/wgpu/README.md

@@ -41,8 +41,14 @@ It exports one procedure `GetSurface(wgpu.Instance, glfw.WindowHandle) -> glfw.S
 The procedure will call the needed target specific procedures and return a surface configured
 for the given window.
 
-To support Wayland on Linux, you need to have GLFW compiled to support it, and use
-`-define:WGPU_GFLW_GLUE_SUPPORT_WAYLAND=true` to enable the package to check for Wayland.
-
 Do note that wgpu does not require GLFW, you can use native windows or another windowing library too.
 For that you can take inspiration from `glfwglue` on glueing them together.
+
+### Wayland
+
+GLFW supports Wayland from version 3.4 onwards and only if it is compiled with `-DGLFW_EXPOSE_NATIVE_WAYLAND`.
+
+Odin links against your system's glfw library (probably installed through a package manager).
+If that version is lower than 3.4 or hasn't been compiled with the previously mentioned define,
+you will have to compile glfw from source yourself and adjust the `foreign import` declarations in `vendor:glfw/bindings` to
+point to it.

vendor/wgpu/glfwglue/glue_linux.odin

@@ -3,11 +3,8 @@ package wgpu_glfw_glue
 import "vendor:glfw"
 import "vendor:wgpu"
 
-// GLFW needs to be compiled with wayland support for this to work.
-SUPPORT_WAYLAND :: #config(WGPU_GFLW_GLUE_SUPPORT_WAYLAND, false)
-
 GetSurface :: proc(instance: wgpu.Instance, window: glfw.WindowHandle) -> wgpu.Surface {
-	when SUPPORT_WAYLAND {
+	if glfw.GetPlatform != nil {
 		if glfw.GetPlatform() == glfw.PLATFORM_WAYLAND {
 			display := glfw.GetWaylandDisplay()
 			surface := glfw.GetWaylandWindow(window)
@@ -24,6 +21,10 @@ GetSurface :: proc(instance: wgpu.Instance, window: glfw.WindowHandle) -> wgpu.S
 				},
 			)
 		}
+
+		if glfw.GetPlatform() != glfw.PLATFORM_X11 {
+			panic("wgpu glfw glue: unsupported platform, expected Wayland or X11")
+		}
 	}
 
 	display := glfw.GetX11Display()