fix for #243

[Stemt]

I added:

• The char utf8_name[MAX_PATH] buffer inside Nob_Dir_Entry.nob__private.

I changed:

• FindFirstFile inside nob_dir_entry_open to FindFirstFileW.
• FindNextFile inside nob_dir_entry_next to FindNextFileW.
• WIN32_FIND_DATA inside Nob_Dir_Entry.nob__private to WIN32_FIND_DATAW.
• GetCurrentDirectory inside nob_get_current_dir_temp with GetCurrentDirectoryW.

I tried to keep the memory allocation consistent with the previous behaviour.
So inside get_current_dir_temp() I use the temp allocator for a temporary utf16 buffer, but in the nob_dir_entry functions it uses a the new utf8_name buffer which takes the place of the WIN32_FIND_DATAA.cFileName buffer.

This has the disadvantage that valid file names might not fit inside this new buffer but I think this is a decent compromise as opposed to requiring the use of the temp allocator for example.

To validate that this works I wrote quick little test:

#if 0
cc -Wall -Wextra -Werror -g -o app main.c && ./app
exit 0
#endif

#define NOB_IMPLEMENTATION
#include "nob.h"

int main(void){
  nob_log(NOB_INFO, "current_dir: %s", nob_get_current_dir_temp());
  File_Paths paths = {0};
  assert(read_entire_dir(".", &paths));
  da_foreach(const char*, path, &paths){
    const unsigned char* p = (const unsigned char*) *path;
    fprintf(stderr, "%s", p);
    fprintf(stderr, "\n");
    while(*p != '\0'){
      fprintf(stderr, "%02X ", *p);
      p++;
    }
    fprintf(stderr, "\n");
  }
  return 0;
}

Here is the result before the change:

[INFO] current_dir: C:\msys64\tmp\test_path\t
.
2E
..
2E 2E
app.exe
61 70 70 2E 65 78 65
main.c
6D 61 69 6E 2E 63
nob.h
6E 6F 62 2E 68
t
74 EA 73 74

Here is the result after the change:

[INFO] current_dir: C:\msys64\tmp\test_path\têst
.
2E
..
2E 2E
app.exe
61 70 70 2E 65 78 65
main.c
6D 61 69 6E 2E 63
nob.h
6E 6F 62 2E 68
têst
74 C3 AA 73 74