Revert of Un-nest configs in GN files.

third_party/mesa/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/ui.gni")
 
 config("mesa_headers_config") {
   include_dirs = [ "src/include" ]
   if (use_x11) {
     defines = [ "MESA_EGL_NO_X11_HEADERS" ]
@@ skipping 129 matching lines @@
       "/wd4090",  # 'Operation' : different 'modifier' qualifiers
       "/wd4099",  # Type name struct-vs-class doesn't match.
       "/wd4273",  # Inconsistent DLL linkage.
       "/wd4291",  # No matching operator delete found for placement new.
       "/wd4305",  # Truncation from int to float.
       "/wd4334",  # Result of 32-bit shift implicitly converted to 64 bits.
       "/wd4345",  # POD-type default initializers.
     ]
   }
 }
-
-config("mesa_libglslcommon_warnings") {
-  if (is_clang) {
-    cflags = [
-      # https://bugs.freedesktop.org/show_bug.cgi?id=91645:
-      "-Wno-overloaded-virtual",
-    ]
-  }
-}
 
 static_library("mesa_libglslcommon") {
   sources = [
     "$generated_src_dir/mesa/glcpp-lex.c",
     "$generated_src_dir/mesa/glcpp-parse.c",
     "$generated_src_dir/mesa/glcpp-parse.h",
     "$generated_src_dir/mesa/glsl_lexer.cc",
     "$generated_src_dir/mesa/glsl_parser.cc",
     "$generated_src_dir/mesa/main/dispatch.h",
     "src/src/glsl/ast_expr.cpp",
@@ skipping 85 matching lines @@
     "src/src/glsl/s_expression.h",
 
     # Skipped in the GN build. This file duplicates symbols from errors.c and
     # happens to link in GYP due to static library link ordering.
     #"src/src/glsl/standalone_scaffolding.cpp",
     #"src/src/glsl/standalone_scaffolding.h",
     "src/src/glsl/strtod.c",
     "src/src/glsl/strtod.h",
   ]
 
+  config("mesa_libglslcommon_warnings") {
+    if (is_clang) {
+      cflags = [
+        # https://bugs.freedesktop.org/show_bug.cgi?id=91645:
+        "-Wno-overloaded-virtual",
+      ]
+    }
+  }
+
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
   previous_configs = configs
   configs = []
   configs = [ ":mesa_internal_config" ] + previous_configs + [
               ":mesa_internal_warnings",
               ":mesa_libglslcommon_warnings",
             ]
 
   if (is_clang) {
@@ skipping 458 matching lines @@
         "KEYWORD2=GLAPIENTRY",
       ]
     }
   }
 } else {
   #  Placeholder to allow targets to unconditionally depend on this.
   group("osmesa") {
   }
 }  # !is_android
 # TODO(GYP) Android osmesa_in_lib_dir target.