#455 "_sopen_s" missing in static win32 builds

[Selur]

Something changed between the 5th and the 11th of of January which now causes static win32 builds to be throwing an error that "_sopen_s" is missing.

background: I'm, using the script from https://github.com/jb-alvarado/media-autobuild_suite which always updates to the latest mingw-w64 build.

would be nice if this change could be undone so that win32 static builds would hve no problem with a missing "_sopen_s".