A build property's value is returned empty in runtime when its length

A build property's value is returned empty in runtime when its length
exceeds 92 symbols (91 valid symbols + \0). It is better to catch that
issue on earlier stage, i.e. fail the build with an appropriate message.

For developer's build, show warning message instead of failing the build
(in the latter case, as developers do not usually care about build properties
too much).

Change-Id: I03ced7b486d43a71b1921e0a9c48b43aa30727c7