--- gif2apng-1.8-src/Makefile
+++ gif2apng-1.8-src/Makefile
@@ -11,19 +11,19 @@
 all : $(PROG_NAME)
 
 gif2apng : objdirs $(OBJECTS)
-	$(CC) -o $@ $(OBJECTS) -s -lstdc++ -lz
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJECTS) -lstdc++ -lz -lm
 
 objdirs :
 	mkdir -p $(OBJ_DIRS)
 
 obj/%.o : %.cpp
-	$(CC) -o $@ -c $< $(INCUDE_DIRS) -O2 -Wall -pedantic -lz
+	$(CC) $(CFLAGS) -o $@ -c $< $(INCUDE_DIRS) -Wall -pedantic -lz -lm
 
 obj/%.o : %.c
-	$(CC) -o $@ -c $< $(INCUDE_DIRS) -O2 -Wall -pedantic -lz
+	$(CC) $(CFLAGS) -o $@ -c $< $(INCUDE_DIRS) -Wall -pedantic -lz -lm
 
 obj/%.o : %.cc
-	$(CC) -o $@ -c $< $(INCUDE_DIRS) -O2 -Wall -Wno-sign-compare -Wno-reorder -Wno-maybe-uninitialized -Wno-parentheses -lz
+	$(CC) $(CFLAGS) -o $@ -c $< $(INCUDE_DIRS) -Wall -Wno-sign-compare -Wno-reorder -Wno-maybe-uninitialized -Wno-parentheses -lz -lm
 
 .PHONY : clean