Compile as C++ without errors

[kees-jan]

Hi, I'd really like to use this code in a C++ project. However, when passing the code to g++, there are several errors and warnings. This pull request fixes them.

There are 4 commits

• Modify the make file to use the $(CC) variable as the compiler, instead of invoking gcc directly. This allows experimenting with different compilers
• Modify the code to allow building on 64-bit architectures (most of this work was done and tested on my desktop pc with a regular gcc/g++)
• Fix all the warnings reported by g++ (apparently, it is more picky than gcc)
• Permanently add a C++ version to the Makefile.

The bulk of the work is in the third commit. I'd be much obliged if you merged at least that one :-)

Thanks!

Kees-Jan

[caspervanzoest]

Thank u so much! Now you are expecting a beer in return, I assume? ;-)