bpfloader - fix includes

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I3c46875a34b744c9ff0af2b52b63ecbc9db5c15e
diff --git a/libbpf_android/include/libbpf_android.h b/libbpf_android/include/libbpf_android.h
index 7811179..9a55f3e 100644
--- a/libbpf_android/include/libbpf_android.h
+++ b/libbpf_android/include/libbpf_android.h
@@ -20,6 +20,8 @@
 #include <libbpf.h>
 #include <linux/bpf.h>
 
+#include <fstream>
+
 namespace android {
 namespace bpf {