--- a/Makefile
+++ b/Makefile
@@ -53,26 +53,23 @@
 #
 # GNU gcc
 #
-CC = gcc
-CFLAGS = -O2
+CFLAGS += -Wall
 
 all: mpeg2decode mpeg2encode
 
 mpeg2decode:
-	cd src/mpeg2dec; make 'CC=$(CC)' \
-	'CFLAGS=$(CFLAGS) $(USE_DISP) $(USE_SHMEM) $(INCLUDEDIR)' \
-	'LIBS=$(LIBS)' 'LIBRARYDIR=$(LIBRARYDIR)'
+	cd src/mpeg2dec && $(MAKE)
 
 mpeg2encode:
-	cd src/mpeg2enc; make 'CC=$(CC)' 'CFLAGS=$(CFLAGS)'
+	cd src/mpeg2enc && $(MAKE)
 
 pc:
-	cd src/mpeg2dec; make pc 'CC=$(CC)' 'CFLAGS=$(CFLAGS)'
-	cd src/mpeg2enc; make pc 'CC=$(CC)' 'CFLAGS=$(CFLAGS)'
+	cd src/mpeg2dec && $(MAKE) pc
+	cd src/mpeg2enc && $(MAKE) pc
 
 clean:
-	cd src/mpeg2dec; make clean
-	cd src/mpeg2enc; make clean
+	cd src/mpeg2dec && $(MAKE) clean
+	cd src/mpeg2enc && $(MAKE) clean
 
 test:
 	cd verify; ./verify
--- a/src/mpeg2dec/Makefile
+++ b/src/mpeg2dec/Makefile
@@ -60,8 +60,7 @@
 #
 # GNU gcc
 #
-CC = gcc
-CFLAGS = -O2 $(USE_DISP) $(USE_SHMEM) $(INCLUDEDIR) $(TRACE) $(VERBOSE) $(VERIFY) $(WARNINGS)
+CFLAGS += -Wall
 
 OBJ = mpeg2dec.o getpic.o motion.o getvlc.o gethdr.o getblk.o getbits.o store.o recon.o spatscal.o idct.o idctref.o display.o systems.o subspic.o verify.o
 
@@ -76,7 +75,7 @@
 	coff2exe mpeg2dec
 
 mpeg2decode: $(OBJ)
-	$(CC) $(CFLAGS) $(LIBRARYDIR) -o mpeg2decode $(OBJ) -lm $(LIBS)
+	$(CC) $(CFLAGS) $(LDFLAGS) $(LIBRARYDIR) -o mpeg2decode $(OBJ) -lm $(LIBS)
 
 display.o : display.c config.h global.h mpeg2dec.h 
 getbits.o : getbits.c config.h global.h mpeg2dec.h 
--- a/src/mpeg2enc/Makefile
+++ b/src/mpeg2enc/Makefile
@@ -32,8 +32,7 @@
 #
 # GNU gcc
 #
-CC = gcc
-CFLAGS = -O2 -Wall
+CFLAGS += -Wall
 
 OBJ = mpeg2enc.o conform.o putseq.o putpic.o puthdr.o putmpg.o putvlc.o putbits.o motion.o predict.o readpic.o writepic.o transfrm.o fdctref.o idct.o quantize.o ratectl.o stats.o
 
@@ -48,7 +47,7 @@
 	coff2exe mpeg2enc
 
 mpeg2encode: $(OBJ)
-	$(CC) $(CFLAGS) -o mpeg2encode $(OBJ) -lm
+	$(CC) $(CFLAGS) $(LDFLAGS) -o mpeg2encode $(OBJ) -lm
 
 conform.o : conform.c config.h global.h mpeg2enc.h 
 fdctref.o : fdctref.c config.h