Remove duplicate journal writing code (and fix it at the same time)

Makefile

@@ -1,10 +1,10 @@
-all: allocator.o blockstore.o blockstore_init.o blockstore_open.o blockstore_read.o \
+all: allocator.o blockstore.o blockstore_init.o blockstore_open.o blockstore_journal.o blockstore_read.o \
 	blockstore_write.o blockstore_sync.o blockstore_stable.o crc32c.o ringloop.o test
 clean:
 	rm -f *.o
 crc32c.o: crc32c.c
 	g++ -c -o $@ $<
 %.o: %.cpp blockstore.h
-	g++ -c -o $@ $<
+	g++ -Wall -Wno-sign-compare -Wno-parentheses -c -o $@ $<
 test: test.cpp
 	g++ -o test -luring test.cpp