Added a definition for M_PI in the code to resolve a compilation error encountered when building OpenCV on the MSYS2 environment. The M_PI constant was not defined, causing the compilation to fail.
Fix to convert float32 to int32/uint32 with rounding to nearest (ties to even). #24271
Fix https://github.com/opencv/opencv/issues/24163
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake
(carotene is BSD)
gcc 10+ has renamed this option, therefore check for gcc version before
deciding which name to use for opt parameter
Signed-off-by: Khem Raj <raj.khem@gmail.com>
