Disable finite-math-only option with ENABLE_FAST_MATH=1 case to handle NaN and Inf checks correctly.

* Added NEON support in builds for Windows on ARM

* Fixed `HAVE_CPU_NEON_SUPPORT` display broken during compiler test

* Fixed a build error prior to Visual Studio 2022

- improve compatibility with further compiler versions
- warnings are not errors by default

- avoid missing of necessary library dependencies

- includes workaround for preprocessor non-compliance
- enable attribute syntax checking in msvc

* [build][option] Introduce `OPENCV_DISABLE_THREAD_SUPPORT` option.

The option forces the library to build without thread support.

* update handling of OPENCV_DISABLE_THREAD_SUPPORT

- reduce amount of #if conditions

* [to squash] cmake: apply mode vars in toolchains too
Co-authored-by: NAlexander Alekhin <alexander.a.alekhin@gmail.com>

(4.x) build: Xcode 12 support

* build: xcode 12 support, cmake fixes

* ts: eliminate clang 11 warnigns

* 3rdparty: clang 11 warnings

* features2d: eliminate build warnings

* test: warnings

* gapi: warnings from 18928

* Ignore clang warnings for deprecated enum+enum operations in mat.inl.hpp

* build: added customization macros, cmake flags for OpenCV build

  * add -Wno-psabi when using GCC 6
  * add -Wundef for CUDA 10
  * add -Wdeprecated-declarations when using GCC 7
  * add -Wstrict-aliasing and -Wtautological-compare for GCC 7
  * replace cudaThreadSynchronize with cudaDeviceSynchronize

- builds with CMAKE_SKIP_RPATH=ON should properly find project .so files from <build>/lib directory
- $ORIGIN doesn't work properly in cross-compilation mode

 - allow cmake to check sanity of vsx aligned ld/st
 - force universal intrinsics v_load_aligned/v_store_aligned
   to failback to unaligned ld/st if cmake runtime vsx aligned test fail

* Enabled -Wnarrowing warning

* Fixed type narrowing issues

* Cast python constants

* Use long long for python constants

* Use int for python constants with fallback to long

* Update cv2.cpp

Avoids passing -Wall, which will enable literally every warning in
Clang. Avoids passing -ffunction-sections etc to clang-cl, which each
generate warnings.

* trying to fix the custom AVX2 builder test failures (false alarms)

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* seemingly disabled false alarm warning in surf.cpp; increased tolerance thresholds in the tests for SolvePnP and in DNN/ENet