I tried an MSVC build of plugin_http.dll from the dsp generated by toolbox.
Build failed with numerous errors.
Added code to http.c as follows:
#if (defined( WIN32 ))
# include <time.h>
# include "dirent.h"
# define S_ISDIR(a) (((a) & S_IFMT) == S_IFDIR)
#endif
Copied a windows port of dirent.h (no .c file needed) into module/control.
Built clean and seems to run fine (replacing libhttp_plugin.dll).
Tried same test using dirent.h and dirent.c from src/extras. Compiled clean when added to project but did not work at runtime. Didn't look into why.
If this is important to anybody, let me know.