Propagate headers from bazel to mixed builds

Bug: 208503274
Test: mixed_libc.sh
Change-Id: I0be57f2a22f48be3a919208db4034d2bd03c18c0
diff --git a/cc/linkable.go b/cc/linkable.go
index 560c9de..02d7047 100644
--- a/cc/linkable.go
+++ b/cc/linkable.go
@@ -384,9 +384,13 @@
 
 	includes := android.PathsForBazelOut(ctx, ccInfo.Includes)
 	systemIncludes := android.PathsForBazelOut(ctx, ccInfo.SystemIncludes)
+	headers := android.PathsForBazelOut(ctx, ccInfo.Headers)
 
 	return FlagExporterInfo{
 		IncludeDirs:       android.FirstUniquePaths(includes),
 		SystemIncludeDirs: android.FirstUniquePaths(systemIncludes),
+		GeneratedHeaders:  headers,
+		// necessary to ensure generated headers are considered implicit deps of dependent actions
+		Deps: headers,
 	}
 }