I need to be able to compile my application in Linux, Windows and Mac using compiler tools supported by R. For windows this means that I must use Mingw-W64 vs with GCC 4.9.3 (https://github.com/rwinlib/r-base#readme). ;
1. Linux: I understand that GCC supports Cilk Plus since GCC 4.9. Is Cilk Plus already a part of GCC 4.9.3 or does it need to be installed separately?
2. On Windows, is Cilk Plus available for the Mingw-W64 toolchain. If not, can it be added and used as another library?
3. Are there any special issues with Mac OS?
I assume you are interested in using Cilk Plus in an application written in C/C++ since it is an extension to C/C++.
1. Linux: GCC 4.9 started to support Cilk Plus features except for the _Cilk_for keyword (https://gcc.gnu.org/gcc-4.9/changes.html), and GCC 5 started to support full features (https://gcc.gnu.org/gcc-5/changes.html).
2. Windows: No, it is not available for MinGW. However, Cygwin started to release Cilk-enabled GCC package recently.
3. Mac: fairly new OS X does not come with GCC and GNU tools, so you will have to build your own GCC from the latest source code after installing the required development tools. I am not sure if it is feasible for you, but there is also an LLVM/Clang compiler branch that supports Cilk Plus - https://cilkplus.github.io.