examples: improve Makefiles, mostly style issues

[asarhaddon]

Hello. Here are a few suggestions. Most of them are trivial, but some may simplify the usage of these examples as basic run-time tests.

[t-14]

Thank you for your contribution. We adopted everything except "explicitly write project names" which goes in the wrong direction - we want on the contrary to emphasize the use of -P switch, the explicit name format is only kept for backwards compatibility and many project tools only recognize -P syntax. Therefore what I did was rather the opposite, removed remaining instances of explicit project name.