compiling postgres_fdw fails for 9.6.5

Hello,

I am on Cent OS 6.8 machine. The Postgres is already installed in some
install_dir/.
I downloaded the source, configured it with prefix=install_dir and
then moved to contrib/postgres_fdw dir.
However make fails with following error:

gcc -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Wendif-labels
-Wmissing-format-attribute -Wformat-security -fno-strict-aliasing
-fwrapv -fexcess-precision=standard -O2 -fPIC
-I../../src/interfaces/libpq -I. -I. -I../../src/include -D_GNU_SOURCE
-c -o postgres_fdw.o postgres_fdw.c
In file included from ../../src/include/postgres.h:48:0,
from postgres_fdw.c:13:
../../src/include/utils/elog.h:71:28: fatal error: utils/errcodes.h:
No such file or directory
compilation terminated.
make: *** [postgres_fdw.o] Error 1

It gets fixed if I add
-I[install_dir]/include/postgresql/server.

Is there alternative way which would not require this modification.

Thanks.