diff --git a/cpu/native/Makefile.native b/cpu/native/Makefile.native
index ea7a2bc27..2adb48070 100644
--- a/cpu/native/Makefile.native
+++ b/cpu/native/Makefile.native
@@ -14,10 +14,10 @@ NM       ?= nm
 OBJCOPY  ?= objcopy
 STRIP    ?= strip
 ifdef WERROR
-CFLAGSWERROR=-Werror -pedantic -std=c99 -Werror
+CFLAGSWERROR=-Werror
 endif
 CFLAGSNO = -Wall -g -I/usr/local/include $(CFLAGSWERROR)
-CFLAGS  += $(CFLAGSNO) -O
+CFLAGS  += $(CFLAGSNO)
 
 ifeq ($(HOST_OS),Darwin)
 AROPTS = -r