Remove X11 and GTK dependencies from host_forwarder

base/base.gyp

Index: base/base.gyp
===================================================================
--- base/base.gyp	(revision 254431)
+++ base/base.gyp	(working copy)
@@ -102,19 +102,6 @@
           # hence the *_android.cc files are included but the actual code
           # doesn't have OS_ANDROID / ANDROID defined.
           'conditions': [
-            # Host build on linux depends on system.gyp::gtk as
-            # default linux build has TOOLKIT_GTK defined.
-            ['host_os == "linux"', {
-              'sources/': [
-                ['include', '^atomicops_internals_x86_gcc\\.cc$'],
-              ],
-              'dependencies': [
-                '../build/linux/system.gyp:gtk',
-              ],
-              'export_dependent_settings': [
-                '../build/linux/system.gyp:gtk',
-              ],
-            }],
             ['host_os == "mac"', {
               'sources/': [
                 ['exclude', '^native_library_linux\\.cc$'],