A minimal commandline timer in C
    make
    timer [[-m minutes] [-s seconds] | [-t minutes:seconds]] [-hv]
   -m minutes
          number of minutes to count.
   -s seconds
          number of seconds to count.
   -t minutes:seconds
          timestring in minutes:seconds format
   -h     show help information
   -v     show version number
   timer -m 2
   timer -s 30
   timer -t 2:30
- Use standard header for boolean
-  Use block for if
- Initialize every variable with value
-  Use unisigned intfor min and sec
-  timer -t :segfaults
-  Either -s -mor-tflags
-  Make cleantarget.PHONY
- Streamline multiple exits
-  Try to be platform independent (unistd.h)
- Try to use safe versions of string functions
- Write comparisons in the way that left side is constant.
- const correctness on each function parameter and, if applicable, on variables
