Document how to build portable, cross-platform binaries

Ninguém assumiu esta issue ainda.

Creating C++ binaries portable to a given platform (osx, linux, windows) or platform version (ubuntu precise or trusty) is absolutely feasible but a poorly documented topic. Often our goal at Mapbox is to support the latest C++11 and C++14 features but maintain code portable to older operating systems like Windows 7, OS X 10.8, and Ubuntu Precise, or RHEL 6/7. This is also feasible. For example its possible to run C++14 binaries on AWS lambda (built on ubuntu precise) even though you can't easily compile them on AWS Lambda.

We should document how Mapbox writes and distributes portable C?C++ code to make clear when this approach is advantageous and when it is not. And to ensure the techniques are robust and replicable.

This issue is to track:

- [ ] getting this all documented here
- [ ] Moving the content from https://github.com/mapbox/node-pre-gyp/wiki/External-libraries to this future doc
- [ ] Moving binary portability FAQ from https://github.com/mapbox/node-pre-gyp/wiki/FAQ#frequently-ask-questions-about-node-pre-gyp to here

Comece revisando a página wiki „External libraries“ do node-pre-gyp e o FAQ de portabilidade de binários vinculado na issue. Consolide o material relevante na documentação planejada, abordando quando binários portáveis de C/C++ são vantajosos e como o Mapbox os escreve e distribui. O trabalho estará concluído quando o tópico estiver documentado aqui e ambas as fontes vinculadas tiverem sido migradas.

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