update gitignore
diff --git a/.gitignore b/.gitignore
index 3eb1cf4..3233540 100644
--- a/.gitignore
+++ b/.gitignore
@@ -40,3 +40,4 @@
 sgx_unwind/libunwind/autom4te.cache/*
 sgx_unwind/libunwind/configure
 sgx_unwind/libunwind/src/Makefile.in
+sgx_unwind/libunwind/m4/*