diff --git a/src/Makefile b/src/Makefile
index abed8af..26061fa 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -6,9 +6,9 @@
 #### CFLAGS	Flags to pass to C compiler.
 
 INCDIR		= .
-CC		= cc
+CC		?= gcc
 
-CFLAGS		= -O
+CFLAGS		?= -O2
 LIBS		= -lm
 
 all:		psipred psipass2 chkparse seq2mtx pfilt
@@ -20,16 +20,16 @@ clean:
 		/bin/rm -f psipred psipass2 chkparse seq2mtx pfilt
 
 psipred:	sspred_avpred.c ssdefs.h sspred_net.h
-		$(CC) $(CFLAGS) sspred_avpred.c $(LIBS) -o psipred
+		$(CC) $(CFLAGS) $(LDFLAGS) sspred_avpred.c $(LIBS) -o psipred
 
 psipass2:	sspred_hmulti.c ssdefs.h sspred_net2.h
-		$(CC) $(CFLAGS) sspred_hmulti.c $(LIBS) -o psipass2
+		$(CC) $(CFLAGS) $(LDFLAGS) sspred_hmulti.c $(LIBS) -o psipass2
 
 chkparse:	chkparse.c
-		$(CC) $(CFLAGS) chkparse.c $(LIBS) -o chkparse
+		$(CC) $(CFLAGS) $(LDFLAGS) chkparse.c $(LIBS) -o chkparse
 
 seq2mtx:	seq2mtx.c
-		$(CC) $(CFLAGS) seq2mtx.c $(LIBS) -o seq2mtx
+		$(CC) $(CFLAGS) $(LDFLAGS) seq2mtx.c $(LIBS) -o seq2mtx
 
 pfilt:		pfilt.c
-		$(CC) $(CFLAGS) pfilt.c $(LIBS) -o pfilt
+		$(CC) $(CFLAGS) $(LDFLAGS) pfilt.c $(LIBS) -o pfilt