Introduced here:

https://github.com/neovim/neovim/commit/4bfac00aa389487c4f11d34e7a3e96e4a1116800#diff-2bf87eef9f7b99dcea4b0c55beee2d63R78

The previous defaults were including the nvim suffix, causing it to
apear twice in the final paths.

kXDGDataHome and kXDGConfigHome are now set as %LOCALAPPDATA%,
kXDGCacheHome is set as $TEMP.

In Windows there is no distinction between configuration and data
storage, but we don't want to place all files under the same path.
get_xdg_home() now appends a different path suffix for kXDGDataHome.

- Configuration files are saved under %LOCALAPPDATA%\nvim
- Data files are saved under %LOCALAPPDATA%\nvim-data

build: install *.mo into the "standard" directory

Change POROJECT_NAME to 'nvim', and use it as the gettext
domain name. The *.mo files, previously installed as
$runtime/lang/xx/LC_MESSAGES/nvim.mo, are now installed as
$prefix/locale/xx/LC_MESSAGES/nvim.mo.

Problem:    Crash when dragging with the mouse.
Solution:   Add safety check for NULL pointer. Check mouse position for valid
            value. (Hirohito Higashi)

https://github.com/vim/vim/commit/294a7e55b01149154807a23323038784549b8946

---

see: "Crash while mouse-selecting in two-buffer mode"
     https://github.com/vim/vim/issues/486

Fix #3704

Problem:    Compiler warning for possible loss of data.
Solution:   Add a type cast. (Erich Ritz)

https://github.com/vim/vim/commit/5df1ed2de3fa9dcace996b9a0a4c9b3cea79cf1e

Problem:    $HOME in `=$HOME . '/.vimrc'` is expanded too early.
Solution:   Skip over `=expr` when expanding environment names.

https://github.com/vim/vim/commit/be83b73ddb2ee8297037166d243f72e3423a3ce3

---

To reproduce:

```sh
nvim -u NONE -c 'e `=$HOME . "/.vimrc"`'
```

Windows: use $PATHEXT to find executables in path

Windows: include <io.h>