diff --git a/src/Makefile.in b/src/Makefile.in
index 6548d1d4b7..c8ca1462c8 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -16,7 +16,7 @@ AXE=@AXE@
 DDCI=0
 T2MI=0
 
-CFLAGS?=-Wall -Wno-switch -ggdb -fPIC -fno-common -Warray-bounds -O2
+CFLAGS?=-Wall -Wno-switch -ggdb -fPIC -fno-common -Warray-bounds
 CFLAGS += -I../src
 CFLAGS += $(EXTRA_CFLAGS) @CFLAGS@
 LDFLAGS += @LDFLAGS@ -lpthread