diff --git a/Makefile b/Makefile
index 897e777..2e45e1c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,11 +1,17 @@
-DEBUG?= -g -ggdb
 CFLAGS?= -O2 -Wall -W -std=c99
 LDFLAGS= -lm
 
-# Uncomment the following two lines for coverage testing
-#
-# CFLAGS+=-fprofile-arcs -ftest-coverage
-# LDFLAGS+=-lgcov
+# if DEBUG env var is set, we compile with "debug" cflags
+ifeq ($(DEBUG),1)
+	CFLAGS += -g -ggdb -fno-omit-frame-pointer
+	LDFLAGS += -g -ggdb
+endif
+
+# if COV env var is set, we compile with "coverage" cflags
+ifeq ($(COV),1)
+	CFLAGS+=-fprofile-arcs -ftest-coverage
+	LDFLAGS+=-lgcov
+endif
 
 all: rax-test rax-oom-test
 
@@ -14,13 +20,13 @@ rax-test.o: rax.h
 rax-oom-test.o: rax.h
 
 rax-test: rax-test.o rax.o rc4rand.o crc16.o
-	$(CC) -o $@ $^ $(LDFLAGS) $(DEBUG)
+	$(CC) -o $@ $^ $(LDFLAGS)
 
 rax-oom-test: rax-oom-test.o rax.o
-	$(CC) -o $@ $^ $(LDFLAGS) $(DEBUG)
+	$(CC) -o $@ $^ $(LDFLAGS)
 
 .c.o:
-	$(CC) -c $(CFLAGS) $(DEBUG) $<
+	$(CC) -c $(CFLAGS) $<
 
 clean:
 	rm -f rax-test rax-oom-test *.gcda *.gcov *.gcno *.o