[Description][2]:

> Meson is an open source build system meant to be both extremely fast,
> and, even more importantly, as user friendly as possible.
>
> The main design point of Meson is that every moment a developer spends
> writing or debugging build definitions is a second wasted. So is every
> second spent waiting for the build system to actually start compiling
> code.

[1]: http://mesonbuild.com/Quick-guide.html
[2]: http://mesonbuild.com/

If the Meson executable is not found, an error will be thrown by the
shell, so the check is not needed.

Additionally, the environment could be changed in the bee file, so
deterministically continue.

The function `start_cmd()` in the bee shell runs "{@}" causing the
setting of the environment variable to be executed, which is of course
not found.

```
function start_cmd() {
    print_info "${COLOR_CYAN}${@}"
    "${@}"
}
```

Work around it, by setting the environment variable `DESTDIR` outside.