Sorry for the off topic discussion, but I would like to give some attention to FreePascal. In my opinion, it is a great piece of software, and is so underrated. If you find C/C++ too error-prone or hard to learn, Object Pascal is a very good alternative. FreePascal is a multi-platform, Delphi compatibe Object Pascal compiler, can generates pretty optimized native code for multiple architectures (including ARM) and has plenty of libraries. If you already hadn't, please give Lazarus[1] a try, it's a nice RAD IDE (very similar to Borland Delphi 7) shipped with the FreePascal compiler.
If I may also use this opportunity to advertise a Pascal-like language, as it is also severely underrated. The language's name is Nimrod [1], it compiles to C so it is also very portable, uses whitespace to delimit blocks, is statically typed with generics and has great support for metaprogramming. I am developing an IDE for it called Aporia [2], it is written in Nimrod, it definitely doesn't have as many features as Lazarus but it works well as a simple editor. Other nimrod projects can be found in the nimrod-code organisation on github[3].
[1] - http://nimrod-code.org
Does it require a runtime? I mean can I develop an OS with it, without shipping the runtime? What language do you know, where that is possible?