GN: Use lib.unstripped rather than lib.stripped. Add a toolchain.gni

build/config/gcc/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.
 
+import("//build/toolchain/toolchain.gni")
+
 # This config causes functions not to be automatically exported from shared
 # libraries. By default, all symbols are exported but this means there are
 # lots of exports that slow everything down. In general we explicitly mark
 # which functiosn we want to export from components.
 #
 # Some third_party code assumes all functions are exported so this is separated
 # into its own config so such libraries can remove this config to make symbols
 # public again.
 #
 # See http://gcc.gnu.org/wiki/Visibility
 config("symbol_visibility_hidden") {
   # Note that -fvisibility-inlines-hidden is set globally in the compiler
   # config since that can almost always be applied.
   cflags = [ "-fvisibility=hidden" ]
 }
 
 # Settings for executables and shared libraries.
 config("executable_ldconfig") {
   if (is_android) {
     ldflags = [
       "-Bdynamic",
       "-Wl,-z,nocopyreloc",
     ]
   } else {
-    # Android doesn't support rpath.
+    # Note: Android doesn't support rpath.
+    rpath_link = ""
+    if (shlib_subdir != ".") {
+      rpath_link = "${shlib_subdir}/"
+    }
     ldflags = [
       # Want to pass "\$". GN will re-escape as required for ninja.
-      "-Wl,-rpath=\$ORIGIN/",
-      "-Wl,-rpath-link=",
+      "-Wl,-rpath=\$ORIGIN/${rpath_link}",
+      "-Wl,-rpath-link=${rpath_link}",
 
       # Newer binutils don't set DT_RPATH unless you disable "new" dtags
       # and the new DT_RUNPATH doesn't work without --no-as-needed flag.
       "-Wl,--disable-new-dtags",
     ]
   }
 }
 
 config("no_exceptions") {
   cflags_cc = [ "-fno-exceptions" ]
   cflags_objcc = cflags_cc
 }