--- libmng-1.0.10/makefiles/makefile.linux
+++ libmng-1.0.10/makefiles/makefile.linux
@@ -44,7 +44,7 @@ WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
 
 # for pgcc version 2.95.1, -O3 is buggy; don't use it.
 
-CFLAGS=-I$(ZLIBINC) -I$(JPEGINC) -I$(LCMSINC) -Wall -O3 -funroll-loops \
+CFLAGS=-I$(ZLIBINC) -I$(JPEGINC) -I$(LCMSINC) $(RPM_OPT_FLAGS) \
 	$(OPTIONS) $(ALIGN) # $(WARNMORE) -g
 LDFLAGS=-L. -Wl,-rpath,. \
 	-L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) \