adding a module for general handy functions regarding compilers
adding file for general handy functions regarding targets
bugfix: adding proper distinction between C and CXX when enabling extra compiler
warnings
adding CMAKE_COMPILER_IS_CLANG in case it is not already defined and the
toolchain in use is in fact clang
Adding module providing a common an portable interface for disabling compiler
extensions (helps writing portable code)
removing debug message left behind.
merging upstream branch