diff --git a/Makefile.am b/Makefile.am
index beeb1d0d..7dac9097 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -69,7 +69,7 @@ OT_INTERNAL_SOUP_LIBS = $(OT_DEP_SOUP_LIBS)
 endif
 
 libgsystem_srcpath := src/libgsystem
-libgsystem_cflags = $(OT_INTERNAL_GIO_UNIX_CFLAGS)
+libgsystem_cflags = $(OT_INTERNAL_GIO_UNIX_CFLAGS) -I$(srcdir)/src/libgsystem
 libgsystem_libs = $(OT_INTERNAL_GIO_UNIX_LIBS)
 if !TRIGGERS_ONLY
 include src/libgsystem/Makefile-libgsystem.am
diff --git a/src/libgsystem b/src/libgsystem
index ccf0438a..9c81ddf4 160000
--- a/src/libgsystem
+++ b/src/libgsystem
@@ -1 +1 @@
-Subproject commit ccf0438a8fa47e7fa1cf5e87c41896f29b81b276
+Subproject commit 9c81ddf47df29f68788d7b040fbe398b36cda92c