[packaging] libapr README url fix patch

[Boris Kolpackov]

Dale Lukas Peterson <hazelnusse at gmail.com> writes:

> So the source of truth of the header is really the include directories like
> you mentioned. If for some reason the generated single header was different
> from the one that is committed (for example due to environment or Python
> differences), then what is tested (generated single header) is not the same
> as what is committed.

Yes, while theoretically possible, since the documentation recommends
"to just copy catch.hpp to your project", I think we can assume it is
good.

In any case, I tried to switch to using multi-header variant (what you
call the source of truth) but immediately ran into problems:

boris:
  Hi Phil, so our attempt to package the multi-header variant quickly ran
  into a roadblock: the directory structure inside include/ does not have
  the catch2/ prefix which appears to be the canonical/recommended way (all
  the examples and some headers include as <catch2/catch.hpp>).
  
  So for now we will go with the single_include/ variant but can easily
  adjust once you figure out the "one true way" ;-). Sounds good?
  
philsquared:
  that could be part of the restructuring that I suspected may be happening
  so, yeah, sounds sensible


> I saw your build2 branch on your catch2 fork and look forward to seeing
> this come to a conclusion so I can start using build2 for some projects :)

Here it is:

https://github.com/boris-kolpackov/Catch2/tree/build2

As mentioned above, it still uses single_include/. I've added build support
for examples and tests (in projects/) that use the <catch2/catch.hpp>
inclusion scheme.

Overall, I think it's in a pretty good shape:

https://ci.cppget.org/@da799a24-4d16-4e29-b3c6-c22ef27a3f8c

There are a couple of TODO items that I think can be fixed by studying
the CMake files more intently, if you want to take a stab at that.
Otherwise I think it's good for a PR.

Finally, you had this comment in your buildfile:

# TODO: figure out why this doesn't work:
# hxx{catch catch_reporter_automake catch_reporter_tap catch_reporter_teamcity}:
#

The reason this doesn't work is because these targets are declared as being
in the output directory, not source. This should work, however:

hxx{catch \
    catch_reporter_automake \
    catch_reporter_tap \
    catch_reporter_teamcity}@./: ...

There are some examples/explanation of this in the manual (search for '@./').