Add more libraries

[wfrisch]

Perpetual issue.

[wfrisch]

A couple of candidates:

• talloc/libreplace "a hierarchical, reference counted memory pool system with destructors."
• libiberty "a software library with a collection of subroutines used by various GNU programs"
• ffmpeg "a suite of libraries and programs for handling video, audio, and other multimedia files and streams" Giant. It breaks the indexer currently.
• angle A conformant OpenGL ES implementation
• boost a set of libraries for the C++ programming language
• scintilla a free, open source library that provides a text editing component function
• nghttp2 HTTP/2 C Library and tools

[wfrisch]

added nghttp2: https://github.com/wfrisch/idlib/commit/e20d9759a17b3196a3296af22370f23b7e0ecb01

[wfrisch]

• googletest embedded in many packages and also in our libraries themselves