Add Global ThinLTO option (2nd try) am: 8ea56f9da9 am: 370a0be4b8 am: 2d2452c88e am: 2168e3ba48

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/1857453

Change-Id: I7391e9e298f6736359b2e61c0c535bfa4d00b95c
diff --git a/android/variable.go b/android/variable.go
index 4a82f23..e7641af 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -116,6 +116,8 @@
 			Shared_libs       []string
 
 			Cmdline []string
+			Srcs         []string
+			Exclude_srcs []string
 		}
 
 		// eng is true for -eng builds, and can be used to turn on additionaly heavyweight debugging