Parallel make fails

[nisargshah95]

Invoking make with -j<n> fails with the following error -

osboxes@osboxes:~/YCSB-C$ make -j3
make -C core
make -C db
make -C redis
make[1]: Entering directory '/home/osboxes/YCSB-C/core'
g++ -std=c++11 -c -g -Wall core_workload.cc -o core_workload.o
make[1]: Entering directory '/home/osboxes/YCSB-C/db'
g++ -std=c++11 -c -g -Wall -fgnu-tm -I../ db_factory.cc -o db_factory.o
make[1]: Entering directory '/home/osboxes/YCSB-C/redis'
g++    -c -o ../db/redis_db.o ../db/redis_db.cc
In file included from ../db/redis_db.cc:6:0:
../db/redis_db.h:9:21: fatal error: core/db.h: No such file or directory
 #include "core/db.h"
                     ^
compilation terminated.
<builtin>: recipe for target '../db/redis_db.o' failed
make[1]: *** [../db/redis_db.o] Error 1
make[1]: Leaving directory '/home/osboxes/YCSB-C/redis'
Makefile:12: recipe for target 'redis' failed
make: *** [redis] Error 2
make: *** Waiting for unfinished jobs....
g++ -std=c++11 -c -g -Wall -fgnu-tm -I../ redis_db.cc -o redis_db.o
g++ -std=c++11 -c -g -Wall -fgnu-tm -I../ hashtable_db.cc -o hashtable_db.o
make[1]: Leaving directory '/home/osboxes/YCSB-C/core'
make[1]: Leaving directory '/home/osboxes/YCSB-C/db'

Simply invoking make builds successfully.