Check for unused variables in GN.

third_party/yasm/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.
 
 # The yasm build process creates a slew of small C subprograms that
 # dynamically generate files at various point in the build process.  This makes
 # the build integration moderately complex.
 #
 # There are three classes of dynamically generated files:
 #   1) C source files that should be included in the build (eg., lc3bid.c)
@@ skipping 23 matching lines @@
   config_makefile = "source/config/$os/Makefile"
   version_file = "version.mac"
 
   import("//build/compiled_action.gni")
 
   config("yasm_config") {
     include_dirs = [
       "source/config/$os",
       "source/patched-yasm",
     ]
-    inputs = [
-      config_makefile,
-      "source/config/$os/config.h",
-      "source/config/$os/libyasm-stdint.h",
-    ]
     defines = [ "HAVE_CONFIG_H" ]
     if (is_posix) {
       cflags = [ "-std=gnu99" ]
     }
   }
 
   executable("genmacro") {
     sources = [ "source/patched-yasm/tools/genmacro/genmacro.c" ]
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [ ":yasm_config",
@@ skipping 314 matching lines @@
     outputs = [ "$yasm_gen_include_dir/license.c" ]
     args = [
       "license_msg",
       rebase_path(outputs[0], root_build_dir),
       rebase_path(sources[0], root_build_dir),
     ]
   }
 
   compiled_action("generate_module") {
     tool = ":genmodule"
+    inputs = [ config_makefile ]
     sources = [ "source/patched-yasm/libyasm/module.in" ]
     outputs = [ "$target_gen_dir/module.c" ]
     args = [
       rebase_path(sources[0], root_build_dir),
       rebase_path(config_makefile, root_build_dir),
       rebase_path(outputs[0], root_build_dir),
     ]
   }
 
   compiled_action("generate_version") {
     tool = ":genversion"
     outputs = [ "$target_gen_dir/$version_file" ]
     args = [
       rebase_path(outputs[0],
       root_build_dir)
     ]
   }
 
   action("generate_x86_insn") {
     script = "source/patched-yasm/modules/arch/x86/gen_x86_insn.py"
     # Output eventually #included by source/patched-yasm/frontends/yasm/x86id.c
     outputs = [
       "$yasm_gen_include_dir/x86insns.c",
       "$yasm_gen_include_dir/x86insn_gas.gperf",
       "$yasm_gen_include_dir/x86insn_nasm.gperf",
     ]
     args = [ rebase_path(yasm_gen_include_dir, root_build_dir) ]
   }
 }