--- a/Makefile
+++ b/Makefile
@@ -18,10 +18,9 @@
 CC=gcc
 AR=ar
 RANLIB=ranlib
-LDFLAGS=
 
 BIGFILES=-D_FILE_OFFSET_BITS=64
-CFLAGS=-Wall -Winline -O2 -g $(BIGFILES)
+CFLAGS+=-Wall -Winline $(BIGFILES) $(CPPFLAGS)
 
 # Where you want it installed when you do 'make install'
 PREFIX=/usr/local
--- a/Makefile-libbz2_so
+++ b/Makefile-libbz2_so
@@ -24,7 +24,7 @@
 SHELL=/bin/sh
 CC=gcc
 BIGFILES=-D_FILE_OFFSET_BITS=64
-CFLAGS=-fpic -fPIC -Wall -Winline -O2 -g $(BIGFILES)
+CFLAGS+=-fpic -fPIC -Wall -Winline $(BIGFILES) $(CPPFLAGS)
 
 OBJS= blocksort.o  \
       huffman.o    \