build: add Fyne/GLFW native deps to dev shell

Add libGL, mesa, wayland, libxkbcommon and the X client libraries the
Fyne cgo toolchain links against, plus LIBRARY_PATH so Go's linker finds
them (it does not read NIX_LDFLAGS).

flake.nix

@@ -30,12 +30,39 @@
             libjpeg_turbo
             pipewire
             xdg-desktop-portal
+            # Fyne / GLFW (cgo) native dependencies.
+            libGL
+            mesa
+            wayland
+            libxkbcommon
+            libX11
+            libXrandr
+            libXi
+            libXcursor
+            libXinerama
+            libXxf86vm
           ];
 
           # Make turbojpeg resolve via pkg-config for cgo builds.
           PKG_CONFIG_PATH = "${pkgs.libjpeg_turbo.dev}/lib/pkgconfig";
           LD_LIBRARY_PATH = "${pkgs.libjpeg_turbo.out}/lib";
 
+          # Fyne/GLFW link against X11, Wayland, GL and misc libs. Go's cgo
+          # linker does not read NIX_LDFLAGS, so expose the runtime lib dirs
+          # via LIBRARY_PATH for the link step.
+          LIBRARY_PATH = with pkgs; lib.makeLibraryPath [
+            libGL
+            mesa
+            wayland
+            libxkbcommon
+            libX11
+            libXrandr
+            libXi
+            libXcursor
+            libXinerama
+            libXxf86vm
+          ];
+
           # Nix's libspa-0.2.pc emits -fno-strict-aliasing/-fno-strict-overflow
           # which Go's cgo rejects unless explicitly allowed.
           CGO_CFLAGS_ALLOW = "-fno-strict-overflow|-fno-strict-aliasing";