Gcc: Suppress warnings in third_party

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 184 matching lines @@
       "//build/win:default_exe_manifest",
     ]
   }
 
   config("yasm_warnings") {
     if (is_clang) {
       cflags = [
         # reg3264type in x86expr.c is unused.
         "-Wno-unused-local-typedef",
       ]
+    } else if (is_linux) {
+      cflags = [
+        # dosexe_objfmt_output ignores the return value of ftruncate.
+        "-Wno-unused-result",
+      ]
     }
   }
 
   executable("yasm") {
     sources = [
       "source/patched-yasm/frontends/yasm/yasm-options.c",
       "source/patched-yasm/frontends/yasm/yasm.c",
       "source/patched-yasm/libyasm/assocdat.c",
       "source/patched-yasm/libyasm/bc-align.c",
       "source/patched-yasm/libyasm/bc-data.c",
@@ skipping 318 matching lines @@
 
     # 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) ]
   }
 }