Allow dependencies of toolchains in GN.

build/toolchain/gcc_toolchain.gni

 # 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.
 
 # This template defines a GCC toolchain.
 #
 # It requires the following variables specifying the executables to run:
 #  - cc
 #  - cxx
 #  - ar
 #  - ld
 # and the following which is used in the toolchain_args
 #  - toolchain_cpu_arch  (What "cpu_arch" should be set to when invoking a
 #                         build using this toolchain.)
 #  - toolchain_os  (What "os" should be set to when invoking a build using this
 #                   toolchain.)
 #
 # Optional parameters:
 #  - libs_section_prefix
 #  - libs_section_postfix
 #      The contents of these strings, if specified, will be placed around
 #      the libs section of the linker line. It allows one to inject libraries
 #      at the beginning and end for all targets in a toolchain.
+#  - deps
+#      Just fowarded to the toolchain definition.
 template("gcc_toolchain") {
   toolchain(target_name) {
     assert(defined(invoker.cc), "gcc_toolchain() must specify a \"cc\" value")
     assert(defined(invoker.cxx), "gcc_toolchain() must specify a \"cxx\" value")
     assert(defined(invoker.ar), "gcc_toolchain() must specify a \"ar\" value")
     assert(defined(invoker.ld), "gcc_toolchain() must specify a \"ld\" value")
     assert(defined(invoker.toolchain_cpu_arch),
            "gcc_toolchain() must specify a \"toolchain_cpu_arch\"")
     assert(defined(invoker.toolchain_os),
            "gcc_toolchain() must specify a \"toolchain_os\"")
@@ skipping 66 matching lines @@
       command = "ln -f \$in \$out 2>/dev/null || (rm -rf \$out && cp -af \$in \$out)"
       description = "COPY \$in \$out"
     }
 
     # When invoking this toolchain not as the default one, these args will be
     # passed to the build. They are ignored when this is the default toolchain.
     toolchain_args() {
       cpu_arch = invoker.toolchain_cpu_arch
       os = invoker.toolchain_os
     }
+
+    if (defined(invoker.deps)) {
+      deps = invoker.deps
+    }
   }
 }