Index: lib/Fuzzer/BUILD.gn
===================================================================
--- /dev/null
+++ lib/Fuzzer/BUILD.gn
@@ -0,0 +1,20 @@
+# This build file is provided for downstream gn-based clients of libfuzzer.
+# It is not a part of LLVM build sequence.
+
+source_set("libfuzzer") {
+  sources = [
+    "FuzzerCrossOver.cpp",
+    "FuzzerDriver.cpp",
+    "FuzzerFlags.def",
+    "FuzzerIO.cpp",
+    "FuzzerInterface.cpp",
+    "FuzzerLoop.cpp",
+    "FuzzerMain.cpp",
+    "FuzzerMutate.cpp",
+    "FuzzerSHA1.cpp",
+    "FuzzerSanitizerOptions.cpp",
+    "FuzzerTracePC.cpp",
+    "FuzzerTraceState.cpp",
+    "FuzzerUtil.cpp",
+  ]
+}