hidapi/windows: allow building on Windows, using the SDL C runtime

Signed-off-by: Sam Lantinga <slouken@libsdl.org>

src/hidapi/SDL_hidapi_windows.h

@@ -20,10 +20,14 @@
 */
 
 /* Define standard library functions in terms of SDL */
+#define HIDAPI_USING_SDL_RUNTIME
 #define calloc      SDL_calloc
 #define free        SDL_free
 #define malloc      SDL_malloc
 #define memcmp      SDL_memcmp
+#define snprintf    SDL_snprintf
+#define strlen      SDL_strlen
+#define _strnicmp   SDL_strncasecmp
 #define swprintf    SDL_swprintf
 #define towupper    SDL_toupper
 #define wcscmp      SDL_wcscmp

src/hidapi/windows/hid.c

@@ -57,9 +57,11 @@ typedef LONG NTSTATUS;
 #include "hidapi_hidclass.h"
 #include "hidapi_hidsdi.h"
 
+#ifndef HIDAPI_USING_SDL_RUNTIME
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#endif
 
 #ifdef MIN
 #undef MIN