Add support for incremental build with header files

.gitignore

 .*.swp
 *.o
+*.d
 *.log
 dump.rdb
 redis-benchmark

src/Makefile

@@ -283,14 +283,18 @@ $(REDIS_BENCHMARK_NAME): $(REDIS_BENCHMARK_OBJ)
 dict-benchmark: dict.c zmalloc.c sds.c siphash.c
 	$(REDIS_CC) $(FINAL_CFLAGS) $^ -D DICT_BENCHMARK_MAIN -o $@ $(FINAL_LIBS)
 
+DEP = $(REDIS_SERVER_OBJ:%.o=%.d) $(REDIS_CLI_OBJ:%.o=%.d) $(REDIS_BENCHMARK_OBJ:%.o=%.d)
+-include $(DEP)
+
 # Because the jemalloc.h header is generated as a part of the jemalloc build,
 # building it should complete before building any other object. Instead of
 # depending on a single artifact, build all dependencies first.
 %.o: %.c .make-prerequisites
-	$(REDIS_CC) -c $<
+	$(REDIS_CC) -MMD -o $@ -c $<
 
 clean:
 	rm -rf $(REDIS_SERVER_NAME) $(REDIS_SENTINEL_NAME) $(REDIS_CLI_NAME) $(REDIS_BENCHMARK_NAME) $(REDIS_CHECK_RDB_NAME) $(REDIS_CHECK_AOF_NAME) *.o *.gcda *.gcno *.gcov redis.info lcov-html Makefile.dep dict-benchmark
+	rm -f $(DEP)
 
 .PHONY: clean