Detected by clang trunk:
```
opencv/modules/core/src/ocl.cpp:4337:37: warning: object backing the pointer will be destroyed at the end of the full-expression [-Wdangling]
CV_OCL_CHECK_RESULT(retval, cv::format("clCreateBuffer(capacity=%lld) => %p", (long long int)entry.capacity_, (void*)entry.clBuffer_).c_str());
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
opencv/modules/core/src/ocl.cpp:193:42: note: expanded from macro 'CV_OCL_CHECK_RESULT'
if (0) { const char* msg_ = (msg); CV_UNUSED(msg_); /* ensure const char* type (cv::String without c_str()) */ } \
```
because `cv::format` yields a temporary std::string, and thus `msg_` points to a destroyed buffer.
* 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
New computeECC function, and updated findTransformECC function to make gaussian filtering optional (#13837)
* fix for https://github.com/opencv/opencv/issues/12432 with doc and tests
* Added doc string for new parameter.
* Fixes suggested by Alalek for getting around ABI incompatibility.
* Update to docstring, to remove parameter that isn't relevant.
* More updates based on Alalek's usggestions.
Resize reworked using wide universal intrinsics (#13781)
* Added wide universal intrinsics optimized implementation for 3 channel bit-exact linear resize
* Reworked linear resize using new wide LUT intrinsics
* Fix for VSX intrinsics
All <arm_neon.h> includes in core/cv_cpu_dispatch.h are protected by an
ifndef __CUDACC__ to prevent attempting to use neon intrinsics when
compiling cuda kernels (.cu) -- this prevents hard errors such as
error: identifier "__builtin_neon_qi" is undefined
Add this same protection to flann/dist.h to fix compilation involving
flann.hpp.
* LineIterator witout a Mat
cv::LineIterator can be used without being attached to any cv::Mat, it only needs the size and type of data. An alternative constructor has been defined for that.
In that case, a LineIterator can no more be dereferenced with the * operator, but pos() still returns valid pixel positions.
It can be useful when LineIterator is just used to compute positions of pixels on a line, without requiring to build a Mat just for that.
Use case : with a dataset that would represent a huge image, pixel positions can be pre-computed before querying the dataset API.
* Update imgproc.hpp
removed trailing spaces
* Update drawing.cpp
fixed warning
