[CMake] FindXXX.cmake specification inconsistency

[r.koebler at yahoo.de]

hi,

> The readme is the way it is supposed to be.
ok, thanks.
so I will probably correct the wiki-page and mabe improve the readme.txt
soon.

> However, many of the modules were created before the readme was created.
then I would note this fact in the readme.txt.

> However, the old variables need to be kept as well as the new ones that
> match the readme.txt so that we don't break any existing projects.
hmm. but I would at least mark them as "deprecated" in the
module-documentation.
(and probably remove them in long term).



could you also answer the folowing questions?

- readme.txt also says:

    The following names should not usually be used in CMakeLists.txt
    files, but they may be usefully modified in users'  CMake Caches
    to control stuff.

    XXX_LIBRARY         Name of XXX Library. A User may set this and
                        XXX_INCLUDE_DIR to ignore to force non-use of XXX.
                        It may or may not be required to use XXX.
    XXX_INCLUDE_DIR     Where to find xxx.h, etc.  (XXX_INCLUDE_PATH was
                        considered bad because a path includes an actual
                        filename.)

how does this work? I mean the FindXXX.cmake sets XXX_INCLUDE_DIRS and
XXX_LIBRARIES. then maybe the user sets XXX_LIBRARY and XXX_INCLUDE_DIR,
as mentioned in the readme.txt.
but who takes care about XXX_LIBRARY and XXX_INCLUDE_DIR? aren't these
variables simply ignored??


- considering the cache:
  should XXX_INCLUDE_DIRS and XXX_LIBRARIES *really* be excluded from
  the (user-configurabe) cache?
  (I don't think so, because then it's not possible for the user to
   configure these paths...)



regards,
Roland