Build PPAPI PNaCl Newlib tests with GN

build/toolchain/nacl/BUILD.gn

Index: build/toolchain/nacl/BUILD.gn
diff --git a/build/toolchain/nacl/BUILD.gn b/build/toolchain/nacl/BUILD.gn
index 686960297d403f7725801860811a5c6aee67d5ce..347e663a57e4f1a3b82b5100b90aa0772bb424d0 100644
--- a/build/toolchain/nacl/BUILD.gn
+++ b/build/toolchain/nacl/BUILD.gn
@@ -3,11 +3,9 @@
 # found in the LICENSE file.
 
 import("//build/config/sysroot.gni")
+import("//build/config/nacl/config.gni")
 import("//build/toolchain/nacl_toolchain.gni")
 
-nacl_toolchain_dir = rebase_path("//native_client/toolchain", root_build_dir)
-os_toolchain_dir = "${nacl_toolchain_dir}/${host_os}_x86"
-
 # Add the toolchain revision as a preprocessor define so that sources are
 # rebuilt when a toolchain is updated.
 # Idea we could use the toolchain deps feature, but currently that feature is
@@ -28,7 +26,7 @@ nacl_toolchain("newlib_pnacl") {
   toolchain_package = "pnacl_newlib"
   toolchain_revision = pnacl_newlib_rev
   toolchain_cpu = "pnacl"
-  toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/pnacl-"
+  toolprefix = "${nacl_host_os_toolchain_dir}/${toolchain_package}/bin/pnacl-"
 
   cc = toolprefix + "clang"
   cxx = toolprefix + "clang++"
@@ -48,7 +46,8 @@ nacl_toolchain("glibc_x86") {
   toolchain_package = "nacl_x86_glibc"
   toolchain_revision = nacl_x86_glibc_rev
   toolchain_cpu = "x86"
-  toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/i686-nacl-"
+  toolprefix =
+      "${nacl_host_os_toolchain_dir}/${toolchain_package}/bin/i686-nacl-"
   is_clang = false
   is_nacl_glibc = true
 
@@ -62,7 +61,8 @@ nacl_toolchain("glibc_x64") {
   toolchain_package = "nacl_x86_glibc"
   toolchain_revision = nacl_x86_glibc_rev
   toolchain_cpu = "x64"
-  toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/x86_64-nacl-"
+  toolprefix =
+      "${nacl_host_os_toolchain_dir}/${toolchain_package}/bin/x86_64-nacl-"
   is_clang = false
   is_nacl_glibc = true
 
@@ -78,7 +78,7 @@ template("nacl_clang_toolchain") {
 
   toolchain_package = "pnacl_newlib"
   toolchain_revision = pnacl_newlib_rev
-  toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/" +
+  toolprefix = "${nacl_host_os_toolchain_dir}/${toolchain_package}/bin/" +
                invoker.toolchain_tuple + "-"
 
   nacl_toolchain("clang_newlib_" + toolchain_cpu) {
@@ -96,7 +96,7 @@ template("nacl_irt_toolchain") {
 
   toolchain_package = "pnacl_newlib"
   toolchain_revision = pnacl_newlib_rev
-  toolprefix = "${os_toolchain_dir}/${toolchain_package}/bin/" +
+  toolprefix = "${nacl_host_os_toolchain_dir}/${toolchain_package}/bin/" +
                invoker.toolchain_tuple + "-"
 
   link_irt = rebase_path("//native_client/build/link_irt.py", root_build_dir)