Respect CFLAGS

Index: Makefile.in
--- Makefile.in.orig
+++ Makefile.in
@@ -41,7 +41,7 @@ DEFS= @defrand@ @defno_snprintf@ @safe_mode@
 LIBS += -lm @iberty@
 
 CC=@CC@
-CFLAGS += $(DEBUG) $(SAFEMODE) $(DEFS) -O
+CFLAGS += $(DEBUG) $(SAFEMODE) $(DEFS)
 LDFLAGS += $(LIBS)
 CPPFLAGS +=
 
