diff --git a/Makefile.am b/Makefile.am
index 70a7445694..12aa04464c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -344,7 +344,7 @@ lcov-reset:
 
 lcov-report:
 	@mkdir $(top_builddir)/coverage
-	lcov --capture --compat-libtool --output-file $(top_builddir)/coverage/coverage.info --directory $(top_builddir) --base-directory $(top_srcdir)/src/
+	lcov --capture --compat-libtool --no-external --output-file $(top_builddir)/coverage/coverage.info --directory $(top_builddir) --base-directory $(top_srcdir)/src/
 	lcov --remove $(top_builddir)/coverage/coverage.info '*.h' --output-file $(top_builddir)/coverage/coverage.cleaned.info
 	lcov --remove $(top_builddir)/coverage/coverage.cleaned.info '*/tests/*' --output-file $(top_builddir)/coverage/coverage.cleaned2.info
 	lcov --remove $(top_builddir)/coverage/coverage.cleaned2.info '*NONE*' --output-file $(top_builddir)/coverage/coverage.cleaned3.info