🐳 Move linux pkg_config() calls into separate BUILD.gn files

build/config/linux/dbus/BUILD.gn

Index: build/config/linux/dbus/BUILD.gn
diff --git a/build/linux/unbundle/libxml.gn b/build/config/linux/dbus/BUILD.gn
similarity index 50%
copy from build/linux/unbundle/libxml.gn
copy to build/config/linux/dbus/BUILD.gn
index c481bd3547bb2b268a26e4582f689e53b5514728..a26ca92b5fcfdfd2b175d3cf5d481b75db4cadeb 100644
--- a/build/linux/unbundle/libxml.gn
+++ b/build/config/linux/dbus/BUILD.gn
@@ -4,15 +4,8 @@
 
 import("//build/config/linux/pkg_config.gni")
 
-pkg_config("system_libxml") {
-  packages = [ "libxml-2.0" ]
-}
-
-static_library("libxml") {
-  sources = [
-    "chromium/libxml_utils.cc",
-    "chromium/libxml_utils.h",
-  ]
-
-  public_configs = [ ":system_libxml" ]
+# Note: if your target also depends on //dbus, you don't need to add this
+# config (it will get added automatically if you depend on //dbus).
+pkg_config("dbus") {
+  packages = [ "dbus-1" ]
 }