adds a kludge to avoid including sys/wait.h on travis builds.
adds a kludge to avoid including sys/wait.h on travis builds.

glibersat/firmware,BrewPi/firmware,BrewPi/firmware,glibersat/firmware,BrewPi/firmware,glibersat/firmware,BrewPi/firmware,BrewPi/firmware,glibersat/firmware,BrewPi/firmware,BrewPi/firmware,BrewPi/firmware,glibersat/firmware,glibersat/firmware,glibersat/firmware