gn2bp: ignore -Wmacro-redefined

Test: //net:net
Change-Id: Ic252a5657457d92f87018028eef61f735f7b50c8
diff --git a/tools/gn2bp/Android.bp.swp b/tools/gn2bp/Android.bp.swp
index c2ceaa1..da1b583 100644
--- a/tools/gn2bp/Android.bp.swp
+++ b/tools/gn2bp/Android.bp.swp
@@ -1848,6 +1848,7 @@
     cflags: [
         "-O2",
         "-Wno-error=return-type",
+        "-Wno-macro-redefined",
         "-Wno-missing-field-initializers",
         "-Wno-non-virtual-dtor",
         "-Wno-sign-compare",