In the future, gbenchmark will be build using a cmake waf tool, which will
require cmake to be installed. We add this option so that users without cmake
can continue use the build system with no problems.
waf's terminology might be a bit confusing regarding the word 'target'. As an
attribute for a task generator, it means the paths of the files supposed to be
built. As a command line option (--target), it means the list of names of the
task generators to be used in the build.
Before this commit, only vehicles programs had their task generators' target
parameter value different from the name parameter. Now, there's no distinction
between those two parameters for the case of programs.
If the attribute name is passed, then it is the one used to process the option
--target[s] of waf build. The board name should be used only in configuration
time. The build targets should be board/platform agnostic.
Now, instead of using `waf --target ArduCopter.sitl`, we use `waf --target
ArduCopter` and the binary continues named as "ArduCopter.sitl".
Gustavo Jose de Sousa
Caio Marcelo de Oliveira Filho