which suits linux ? GNU make vs cmake vs codeblocks vs qmake

In front of me some different Technologies and I'm confused between them. GNU make, CMAKE, Qmake, Code::blocks methodology

Code::Blocks uses a custom build system, which stores its information in XML-based project files, but can optionally use external makefiles **says WIKI**

1- What's the difference between CMAKE and GNU MAKE ?

2- If I'm planning for long term relationship with linux what is the best for that ?

3- If I needed to cross-platform some apps, will I need the same technique ?