after command "make iso" i have "/bin/sh: 3: lb: not foundMakefile:81: recipe for target 'clean' failedmake: * [clean] Error 127"

Desired behaviour is to produce a self-descriptive error message, or, better, prevent it from getting this far if it's not installed.

The reason for it is that "clean" target that depends on live-build is executed before the "prepare" target that is checking for live-build among other things and would prevent it from even getting this far.

I believe the cleanest solution is to move environment/dependencies check to ./configure to allow the user to detect and fix any build environmet issues as early as possible. This is also in line with the autotools behaviour.