diff --git a/libsysio/Makefile.am b/libsysio/Makefile.am
index dfa4f9ebfca47ceb9fe467b89b71a3654737c907..43c736a7eb81222ca76007035904d346d594bb8a 100644
--- a/libsysio/Makefile.am
+++ b/libsysio/Makefile.am
@@ -49,7 +49,7 @@ endif
 
 if WITH_LUSTRE_HACK
 # it would be better that let configure script check this
-OPTIONAL_LUSTRE_CFLAGS = -fPIC
+OPTIONAL_LUSTRE_CFLAGS = -fPIC -O0
 endif
 
 AM_CFLAGS = $(OPTIONAL_LUSTRE_CFLAGS)