a large memory buffer on Windows

fil_extend_space_to_desired_size(), os_file_set_size(): Use calloc()
for memory allocation, and handle failures. Properly check the return
status of posix_fallocate().

On Windows, instead of extending the file by at most 1 megabyte at a time,
write a zero-filled page at the end of the file.
According to the Microsoft blog post
https://blogs.msdn.microsoft.com/oldnewthing/20110922-00/?p=9573
this will physically extend the file by writing zero bytes.
(InnoDB never uses DeviceIoControl() to set the file sparse.)

For innodb_plugin, port the XtraDB fix for MySQL Bug#56433
(introducing fil_system->file_extend_mutex). The bug was
fixed differently in MySQL 5.6 (and MariaDB Server 10.0).