AOT: jaotc should provide an option to specify the path to the platform linker

jaotc currently assumes that "ld" is available on the current users PATH when run on Linux, Solaris or MacOSX. In addition, on Windows, we assume that the normal Windows environment variables are properly setup (VS120COMNTOOLS for example) or the Visual Studio installation is in the normal well know paths. We also only support VS2012, VS2013 and VS2015.

In order to be more flexible, jaotc should provide a command line option that would allow a user to specify the path to where these linkers are located.