Merge pull request #29453 from vrabaud:persistence

Replace "static inline" by "inline" in headers #29453

This fixes #29436

I also replaced CV_INLINE which can be removed in a later PR.

I can make a similar PR for 4.x if you want.

### 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
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

modules/stitching/include/opencv2/stitching/detail/util_inl.hpp

@@ -98,30 +98,30 @@ B Graph::walkBreadthFirst(int from, B body) const
 //////////////////////////////////////////////////////////////////////////////
 // Some auxiliary math functions
 
-static inline
+inline
 float normL2(const Point3f& a)
 {
     return a.x * a.x + a.y * a.y + a.z * a.z;
 }
 
 
-static inline
+inline
 float normL2(const Point3f& a, const Point3f& b)
 {
     return normL2(a - b);
 }
 
 
-static inline
+inline
 double normL2sq(const Mat &r)
 {
     return r.dot(r);
 }
 
 
-static inline int sqr(int x) { return x * x; }
-static inline float sqr(float x) { return x * x; }
-static inline double sqr(double x) { return x * x; }
+inline int sqr(int x) { return x * x; }
+inline float sqr(float x) { return x * x; }
+inline double sqr(double x) { return x * x; }
 
 } // namespace detail
 } // namespace cv