Update Makefile

[blshkv]

fixing the issue #52

[dpayne]

Instead of the mkdir, could you put a check to see if it exists and then error out if it doesn?

[blshkv]

That is taken cared automatically by -p parameter

[dpayne]

It's more that I didn't want the install script making an important directory like /usr/local/bin/ without the user knowing very explicitly. It can potentially create a directory with odd permissions. It seems better to fail loudly and force the user to think about what they are doing before making the directory.

[blshkv]

The purpose of this PR is to fix the DESTDIR variable and ability to compile the tool in a sandbox env where there are NO directories at all. So you HAVE to create it or make DESTDIR=/var/tmp install WILL fail.

Feel free to add your other ideas in a different PR, this is not related to this problem. I also disagree with your idea. A regular user will not be able to create a system directory. If a user decided to run "sudo make install" this is not your responsibility to check the integrity and hardening (umask and so on) of his system. it is common that this command will install into /usr/local/bin and it is known that one need to change prefix if needed.

I also do not like static Makefile concept. It's better to use a proper autotools (automake) or cmake tools which are specifically design to check all unthinkable conditions.