- to avoid out of buffer access

- builtin OpenEXR source code is outdated
- external OpenEXR distributions are allowed

- this doesn't make sense in case of multiple inputs

* Fix compile against lapack-3.10.0

Fix compilation against lapack >= 3.9.1 and 3.10.0 while not breaking older versions

OpenCVFindLAPACK.cmake & CMakeLists.txt: determine OPENCV_USE_LAPACK_PREFIX from LAPACK_VERSION

hal_internal.cpp : Only apply LAPACK_FUNC to functions whose number of inputs depends on LAPACK_FORTRAN_STR_LEN in lapack >= 3.9.1

lapack_check.cpp : remove LAPACK_FUNC which is not OK as function are not used with input parameters (so lapack.h preprocessing of "LAPACK_xxxx(...)" is not applicable with lapack >= 3.9.1
If not removed lapack_check fails so LAPACK is deactivated in build (not want we want)

use OCV_ prefix and don't use Global, instead generate OCV_LAPACK_FUNC depending on CMake Conditions

Remove CONFIG from find_package(LAPACK) and use LAPACK_GLOBAL and LAPACK_NAME to figure out if using netlib's reference LAPACK implementation and how to #define OCV_LAPACK_FUNC(f)

* Fix typos and grammar in comments

- FFmpeg 3.4.9