* Add debug build option to MacOs and iOS build scripts

* osx: allow selection of MACOSX_DEPLOYMENT_TARGET

* Add --debug_info flag to iOS and macOS builds for building with debug info

The deprecated flag ENABLE_VSX should not be used to enable this
feature. Instead, use the baseline cpu feature set to determine.

s/last_occurence/last_occurrence/

* fix broken code link

resolves  #15344

* Update stitcher.markdown

* update 3.4 link

* jas_stream: Add definition for L_tmpnam if missing

uClibc-ng for some reason does not provide a definition when some
deprecated APIs are disabled. Value taken from the musl libc.

* 3rdparty: move uClibc-ng workaround into config file

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.

* Fix the detection of XIMEA on Windows (when it has been installed by another user with administrative privileges, for example).

* Change the flow: we first try HKEY_CURRENT_USER key and, if empty, then try HKEY_LOCAL_MACHINE