[MIPS] Adding NaCl/PNaCl support for mipsel to GN

build/config/compiler/BUILD.gn

 # 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/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 517 matching lines @@
         }
       }
       if (arm_tune != "") {
         cflags += [ "-mtune=$arm_tune" ]
       }
     } else if (current_cpu == "arm64") {
       if (is_clang && !is_android && !is_nacl) {
         cflags += [ "--target=aarch64-linux-gnu" ]
         ldflags += [ "--target=aarch64-linux-gnu" ]
       }
-    } else if (current_cpu == "mipsel") {
+    } else if (current_cpu == "mipsel" && !is_nacl) {

[brettw, 2016/08/12 19:52:40]

This nacl check doesn't make immediate sense to me. Why wouldn't the mips arch
variants apply to nacl code?

[lmilko, 2016/08/15 14:56:10]

mipsel-nacl-clang compiler does not need any of the flags defined in this block.
Alternative would be to add !is_nacl checks for each cflags and ldflags, not to
include -fno-integrated-as, --target, -march, -mcpu and dsp flags.

       if (is_clang) {
         # Temporarily needed due to unsupported MIPS macro instructions
         # in inline asm code in third_party projects (libwebp and webrtc).
         # TODO(lmilko) Enable integrated-as.
         cflags += [ "-fno-integrated-as" ]
       }
       if (mips_arch_variant == "r6") {
         if (is_clang) {
           cflags += [
             "--target=mipsel-linux-gnu",
@@ skipping 1013 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }