Merge "Improve error message for dupe srcs in genrule" am: a5969bec06

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/1850000

Change-Id: I9a71dc9959dac54bb2792280be01944fde604a9a
diff --git a/genrule/genrule.go b/genrule/genrule.go
index 1679a57..8282426 100644
--- a/genrule/genrule.go
+++ b/genrule/genrule.go
@@ -294,7 +294,7 @@
 		if _, exists := locationLabels[label]; !exists {
 			locationLabels[label] = loc
 		} else {
-			ctx.ModuleErrorf("multiple labels for %q, %q and %q",
+			ctx.ModuleErrorf("multiple locations for label %q: %q and %q (do you have duplicate srcs entries?)",
 				label, locationLabels[label], loc)
 		}
 	}