Non-targets emitted when using make

[raidiun]

If a target is already up to date, make -prRn emits the message from make as part of the dry run option. Unfortunately, this message looks a lot like a target and so a GNU Make: make target is emitted.

In a similar vein, GNU Make: Makefile is emitted as a target. However, updating a makefile may have a use for auto dependancy options. (Though make does update dependancies of the Makefile automatically prior to executing other targets)

[raidiun]

Related to #8 In that make -prRn will output file prerequisites in a format that looks like a target. Switching the flag as in 376b8e7 does not fix this.

Potential fix buried in exotic-target-names. Fix involves splitting make output on blank lines into "blocks". Blocks that don't actually contain target will have # Not a target: at the start. Other non-target blocks also start with a comment.