Unable to recognize the global variables set in Ubuntu - makefile

Question

I have been following the steps mentioned here Google Weave-Libiota on Ubuntu. It's been successful until running test step. Later on, we need to write a header file defining the api_keys, Client_secret key and client_id and set its path to a Global Environment variable so that the program main.c uses API KEY file through header files and Global variable. But it's not recognizing.
Errors to the command make -C /host/examples/light image:
wozartubuntu#wozartubuntu-iMac:~$ cd libiota/
wozartubuntu#wozartubuntu-iMac:~/libiota$ sudo make -C examples/host/light/
[sudo] password for wozartubuntu:
make: Entering directory '/home/wozartubuntu/libiota/examples/host/light'
gcc -Wall -Werror -Os -fno-builtin -ffunction-sections -fdata-sections -fstack-usage -DIOTA_BUILD_TIME=1485236028 -DSUPPORTS_FLOATING_POINT_FORMAT -I/usr/local/include -std=gnu99 -MMD -I$IOTA_ROOT -I$IOTA_ROOT/include -DJSMN_PARENT_LINKS -DJSMN_SHORT_TOKENS -I$IOTA_ROOT/third_party/jsmn -c -o /home/wozartubuntu/libiota/out/host/examples/light/main.o /home/wozartubuntu/libiota/examples/host/light/main.c
In file included from /home/wozartubuntu/libiota/examples/host/light/main.c:22:0:
/home/wozartubuntu/libiota/include/iota/oauth_keys.h:23:38: fatal error: IOTA_OAUTH2_KEYS_HEADER.h: No such file or directory
compilation terminated.
../../../examples/host/common.mk:33: recipe for target '/home/wozartubuntu/libiota/out/host/examples/light/main.o' failed
make: *** [/home/wozartubuntu/libiota/out/host/examples/light/main.o] Error 1
make: Leaving directory '/home/wozartubuntu/libiota/examples/host/light'
wozartubuntu#wozartubuntu-iMac:~/libiota$
Program causing the error:
/*
* Copyright 2016 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LIBIOTA_INCLUDE_IOTA_OAUTH_KEYS_H_
#define LIBIOTA_INCLUDE_IOTA_OAUTH_KEYS_H_
#include "IOTA_OAUTH2_KEYS_HEADER"
#endif // LIBIOTA_INCLUDE_IOTA_OAUTH_KEYS_H_
How to resolve these errors?