2. I'd assume as lines are normally counted. The number of line-feeds and/or carriage returns in a file. I don't see what the big deal is anyway; if you are at all concerned, just include the license text. Is doing so that big a deal?
Ten lines per function, per header, per library, per program?
Edit: I think you didn't understand LGPL yourself either. I think in the quoted lines, "object code" refers to your code, and accompanying them with a copy of GPL refers to having to release your code under GPL. Or do you think you only have to say you release it under GPL and not actually release it?
If you have just your object code, you are not bound by the license of the library, then you don't need to include it.
If you have just the library header code, then you are not incorporating it into anything else, and have no obligations by the license.
If you have both the library header code incorporated into your object code , then you are bound by the license to provide attribution along with that incorporated object code.
As for you second question, I'd guess lines per file. But it is a bit ambiguous, as almost all legalese is. Again, you could just err toward caution, and include the license text regardless. Are you averse to this for some reason?
Oh, and as per the wiki link, object code is the compiled binary of your source code. At this point, whatever headers you included would already be integrated.
The fact that your understanding of the license is different shows just how sneaky and obfuscated LGPL is.
> Lesser GPL permits use of the library in proprietary programs
That means "in some cases", not "in all cases". Logical fallacy on your part.
> ordinary GPL for a library makes it available only for free programs
Here, GPL'ers contradict themselves (for both senses of "free"). GPL code can, technically, be non-gratis. And GPL code can be used in non-GPL programs (you just can't distribute them easily).
Those terms to which you object mean, I think, the following: If your object code includes bits of the library header files, and if those bits are substantial, then you have to (1) say that you're using the library, (2) say what licence the library is covered by, and (3) include a copy of the documents that define that licence.