C++ dependency blockers

Question

Issue Description:Existing c++ modules has external dependencies to make them build.we have added all dependencies by paths or manually(eg. with .h files),

where calling methods required definitions but still geeting below types of errors:

Error (active)    identifier "HANDLER" is undefined in .CPP files

FYI ..I tried to create a sample project in 2015 and did same things to add external dependencies there its building successfully and no issues.

Background of the project:Module which i am working was built on old platform(vc8)[Analysis did or R&D:same code not working as well for vc8],

now I am building or Migrating same code in new platform 2015(Vc++) and the issue remains the same.

Could you help/suggest us to resolve this kind of issue.(If you have encountered in the past).