Use default optimization level

- Remove -O0 from MAkefile

Author: vrahane

Makefile

@@ -203,7 +203,7 @@ tag: distcheck
 
 cflags := $(CPPFLAGS) -I$(SRCDIR)include
 cflags += -DTINYCBOR_VERSION_SUFFIX=\"$(DIRTYSRC)\"
-cflags += -std=c99 -O0 $(CFLAGS)
+cflags += -std=c99 $(CFLAGS)
 %.o: %.c
 	@test -d $(@D) || $(MKDIR) $(@D)
 	$(CC) $(cflags) $($(basename $(notdir $@))_CCFLAGS) -c -o $@ $<