I have a BSD-licensed piece of code, and I would like to integrate some code licensed under the Boost software license directly in the file, for reasons of portability. The file contains the full BSD 3-clause license in a header at the top.
If I explicitly state the origin of the Boost-licensed code, where it starts and ends in the file, and that it's covered under the boost software license, as well as including a full copy of the Boost license in the code itself, do I need to make any changes to the BSD copyright header (e.g.: stating that it's not all under BSD/that it's all under the BSD license except where explicitly mentioned), or anything else? Or should I include the Boost licensed code in a separate file?