* fix find zlib.so instead of zlib.a when NDK >= 19
On Android platform, `libopencv_imgcodecs.a` is built, expected to
depend on `libz.so`. However, since Android NDK r19, NDK's `libz.a`
is found instead of `libz.so`, leading to link error
(not found libz.a) on machines without same NDK version & direcotry.
Since Android NDK-r19, toolchain pieces are installed to
`$NDK/toolchains/llvm/prebuilt/<host-tag>/...`, including `libz.so`.
Also installed to old paths (`<NDK>/platforms` and `<NDK>/sysroot`)
in NDK r19, r20, r21, but since NDK 22, old paths are removed.
- https://github.com/android/ndk/wiki/Changelog-r19
- https://github.com/android/ndk/wiki/Changelog-r22
With this commit, `libz.so` can be correctly found in NDK<19 and NDK>=19.
`ZLIB_LIBRARIES` is also simplified as `z`, by appending match (regex)
patterns for new toolchain installation directory's libz.so's paths.
* simplify libz.so match pattern for abbreviation
a5a421a9f1