Merge pull request fffaraz#416 from ax3l/topic-spack

Add Spack

Author: fffaraz

README.md

@@ -756,6 +756,7 @@ A curated list of awesome C/C++ frameworks, libraries, resources, and shiny thin
 * [Ninja](https://ninja-build.org/) - A small build system with a focus on speed.
 * [Scons](http://www.scons.org/) - A software construction tool configured with a Python script.
 * [Sconsolidator](http://www.sconsolidator.com/) - Scons build system integration for Eclipse CDT.
+* [Spack](https://spack.io/) - A flexible package manager that supports multiple versions, configurations, platforms, and compilers. [LGPLv2.1]
 * [tundra](https://github.com/deplinenoise/tundra) - High-performance code build system designed to give the best possible incremental build times even for very large software projects.
 * [tup](http://gittup.org/tup/) - File-based build system that monitors in the background for changed files.
 * [Premake](http://premake.github.io) - A tool configured with a Lua script to generate project files for Visual Studio, GNU Make, Xcode, Code::Blocks, and more across Windows, Mac OS X, and Linux.