clang/win/gn: Actually build 32-bit .obj files in 32-bit builds.

build/toolchain/win/BUILD.gn

Index: build/toolchain/win/BUILD.gn
diff --git a/build/toolchain/win/BUILD.gn b/build/toolchain/win/BUILD.gn
index beee0781d673a1ae2e453d07df65371339009c99..303ada556da84ceacbc2d261999ad35508a0fc51 100644
--- a/build/toolchain/win/BUILD.gn
+++ b/build/toolchain/win/BUILD.gn
@@ -282,7 +282,7 @@ if (target_cpu == "x86") {
     toolchain_cpu = "x86"
     prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                          root_build_dir)
-    cl = "${goma_prefix}$prefix/${clang_cl}"
+    cl = "${goma_prefix}$prefix/${clang_cl} -m32"

[Dirk Pranke, 2016/05/06 15:53:58]

Shouldn't this already be being set here:

https://code.google.com/p/chromium/codesearch?q=build%2Fconfig%2Fwin%2FBUILD....

?

[Nico, 2016/05/06 16:21:33]

Oh, great point! It seems to not always have an effect when it's set there. I
unchecked cq and will investigate, thanks.

[Nico, 2016/05/06 20:10:21]

mini_installer does

  configs -= [ "//build/config/compiler:compiler" ]

https://code.google.com/p/chromium/codesearch#chromium/src/chrome/installer/m...

which looks a bit...uh, surprising to me. I guess that means "I mean it" flags
like -m32 / -m64 need to be part of the toolchain instead of the compiler config
then? :-/

     toolchain_os = "win"
     is_clang = true
   }
@@ -321,7 +321,7 @@ template("win_x64_toolchains") {
     toolchain_cpu = "x64"
     prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                          root_build_dir)
-    cl = "${goma_prefix}$prefix/${clang_cl}"
+    cl = "${goma_prefix}$prefix/${clang_cl} -m64"
     toolchain_os = "win"
     is_clang = true