Meta: Port recent changes to gn build

b7f8d7e3570e874cca3127028ed805b87ef56648
048e179572aada0e70376fb46a50e3ad486c8025
6d1a1daff9dbdb03b4e202058adf4f1289f52bf5
04c094343ffcd9fc2012b1e43658e32e3b935642
a6106ca22185cfd3e66207a17e49dafd94dd1ae2

Meta/gn/build/BUILD.gn

@@ -99,7 +99,10 @@ config("compiler_defaults") {
     "-Wall",
     "-Wextra",
   ]
-  cflags += [ "-Wno-unused-parameter" ]
+  cflags += [
+    "-Wno-unused-parameter",
+    "-Wno-invalid-offsetof",
+  ]
   if (is_clang) {
     cflags += [
       "-Wdelete-non-virtual-dtor",

Meta/gn/secondary/Userland/Libraries/LibAccelGfx/BUILD.gn

@@ -14,12 +14,15 @@ shared_library("LibAccelGfx") {
     ]
   }
   sources = [
-    "Canvas.cpp",
     "Canvas.h",
     "Context.cpp",
     "Context.h",
     "Forward.h",
+    "GL.cpp",
+    "GL.h",
     "Painter.cpp",
     "Painter.h",
+    "Program.cpp",
+    "Program.h",
   ]
 }

Meta/gn/secondary/Userland/Libraries/LibWeb/WebIDL/BUILD.gn

@@ -3,6 +3,7 @@ source_set("WebIDL") {
   deps = [ "//Userland/Libraries/LibWeb:all_generated" ]
   sources = [
     "AbstractOperations.cpp",
+    "Buffers.cpp",
     "CallbackType.cpp",
     "DOMException.cpp",
     "OverloadResolution.cpp",