Revert of [GN]: BUILD file housecleaning

build/toolchain/gcc_toolchain.gni

 # Copyright (c) 2013 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/nacl/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/toolchain/ccache.gni")
 import("//build/toolchain/goma.gni")
 import("//build/toolchain/toolchain.gni")
 
@@ skipping 176 matching lines @@
       depsformat = "gcc"
       description = "CXX {{output}}"
       outputs = [
         "{{target_out_dir}}/{{target_output_name}}/{{source_name_part}}.o",
       ]
     }
 
     tool("asm") {
       # For GCC we can just use the C compiler to compile assembly.
       depfile = "{{output}}.d"
-      command = "$cc -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{asmflags}} -c {{source}} -o {{output}}"
+      command = "$cc -MMD -MF $depfile ${rebuild_string}{{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
       depsformat = "gcc"
       description = "ASM {{output}}"
       outputs = [
         "{{target_out_dir}}/{{target_output_name}}/{{source_name_part}}.o",
       ]
     }
 
     tool("alink") {
       rspfile = "{{output}}.rsp"
       arflags = ""
@@ skipping 144 matching lines @@
         is_lsan = false
         is_msan = false
         is_syzyasan = false
         is_tsan = false
       }
     }
 
     forward_variables_from(invoker, [ "deps" ])
   }
 }