Convert third_party source sets to static libraries.

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 86 matching lines @@
     deps = [
       ":yasm_utils",
       "//build/config/sanitizers:deps",
 
       # Default manifest on Windows (a no-op elsewhere).
       "//build/win:default_exe_manifest",
     ]
   }
 
   # Used by both yasm and genperf binaries.
-  source_set("yasm_utils") {
+  static_library("yasm_utils") {
     sources = [
       "source/patched-yasm/libyasm/phash.c",
       "source/patched-yasm/libyasm/xmalloc.c",
       "source/patched-yasm/libyasm/xstrdup.c",
     ]
 
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [
       ":yasm_config",
       "//build/config/compiler:no_chromium_code",
@@ skipping 415 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) ]
   }
 }