Error building with MinGW-w64 in mkdir() in src/supplemental/nanolib/file.c

[brechtsanders]

Describe the bug
When building natively on Windows with MinGW-w64 there was an error in src/supplemental/nanolib/file.c in the following line=

ret = mkdir(fpath, 0777);

The problem is that mkdir() only takes one argument on Windows.

However there seems to be a solution for this in the same file by defining the nano_mkdir() macro.

Replacing the above line with the following does allow it to build:

ret = nano_mkdir(fpath, 0777);

[JaylinYu]

Oh, yep, The code in this file is obsolated mostly, you can remove file_create_dir() API. or wait for our next release