Include stdbool.h when using Visual Studio 2017+

Also cleaned up some incorrect return values from bool functions.

include/SDL3/SDL_stdinc.h

···
 
 #ifndef __cplusplus
 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
+    (defined(_MSC_VER) && (_MSC_VER >= 1910 /* Visual Studio 2017 */)) || \
     defined(SDL_INCLUDE_STDBOOL_H)
 #include <stdbool.h>
 #elif !defined(__bool_true_false_are_defined) && !defined(bool)

src/core/windows/SDL_windows.c

···
 
 BOOL WIN_IsEqualGUID(const GUID *a, const GUID *b)
 {
-    return SDL_memcmp(a, b, sizeof(*a)) == 0;
+    return (SDL_memcmp(a, b, sizeof(*a)) == 0);
 }
 
 BOOL WIN_IsEqualIID(REFIID a, REFIID b)
 {
-    return SDL_memcmp(a, b, sizeof(*a)) == 0;
+    return (SDL_memcmp(a, b, sizeof(*a)) == 0);
 }
 
 void WIN_RECTToRect(const RECT *winrect, SDL_Rect *sdlrect)

src/filesystem/windows/SDL_sysfsops.c

···
         const size_t patternlen = SDL_strlen(path) + 3;
         char *pattern = (char *) SDL_malloc(patternlen);
         if (!pattern) {
-            return -1;
+            return false;
         }
 
         // you need a wildcard to enumerate through FindFirstFileEx(), but the wildcard is only checked in the
···
         WCHAR *wpattern = WIN_UTF8ToStringW(pattern);
         SDL_free(pattern);
         if (!wpattern) {
-            return -1;
+            return false;
         }
 
         WIN32_FIND_DATAW entw;
         HANDLE dir = FindFirstFileExW(wpattern, FindExInfoStandard, &entw, FindExSearchNameMatch, NULL, 0);
         SDL_free(wpattern);
         if (dir == INVALID_HANDLE_VALUE) {
-            WIN_SetError("Failed to enumerate directory");
-            return -1;
+            return WIN_SetError("Failed to enumerate directory");
         }
 
         do {

src/haptic/SDL_haptic.c

···
 
     SDL_ClearError();
 
-    return SDL_SYS_HapticGetEffectStatus(haptic, &haptic->effects[effect]);
+    return (SDL_SYS_HapticGetEffectStatus(haptic, &haptic->effects[effect]) > 0);
 }
 
 bool SDL_SetHapticGain(SDL_Haptic *haptic, int gain)

src/haptic/windows/SDL_dinputhaptic.c

···
         return false;
     }
 
-    return WIN_IsEqualGUID(&hap_instance.guidInstance, &joy_instance.guidInstance);
+    return (WIN_IsEqualGUID(&hap_instance.guidInstance, &joy_instance.guidInstance) == TRUE);
 }
 
 bool SDL_DINPUT_HapticOpenFromJoystick(SDL_Haptic *haptic, SDL_Joystick *joystick)
···
 
     ret = IDirectInputEffect_GetEffectStatus(effect->hweffect->ref, &status);
     if (FAILED(ret)) {
-        return DI_SetError("Getting effect status", ret);
+        DI_SetError("Getting effect status", ret);
+        return -1;
     }
 
     if (status == 0) {
-        return false;
+        return 0;
     }
-    return true;
+    return 1;
 }
 
 bool SDL_DINPUT_HapticSetGain(SDL_Haptic *haptic, int gain)

src/joystick/SDL_joystick.c

···
 
     SDL_LockJoysticks();
     {
-        CHECK_JOYSTICK_MAGIC(joystick, -1);
+        CHECK_JOYSTICK_MAGIC(joystick, false);
 
         if (ball < joystick->nballs) {
             if (dx) {

src/storage/steam/SDL_steamstorage.c

···
 
 static bool STEAM_WriteStorageFile(void *userdata, const char *path, const void *source, Uint64 length)
 {
-    int result = false;
+    bool result = false;
     STEAM_RemoteStorage *steam = (STEAM_RemoteStorage*) userdata;
     void *steamremotestorage = steam->SteamAPI_SteamRemoteStorage_v016();
     if (steamremotestorage == NULL) {

src/thread/windows/SDL_syscond_cv.c

···
         mutex->count = 0;
         mutex->owner = 0;
 
-        result = pSleepConditionVariableSRW(&cond->cond, &mutex->srw, timeout, 0);
+        result = (pSleepConditionVariableSRW(&cond->cond, &mutex->srw, timeout, 0) == TRUE);
 
         // The mutex is owned by us again, regardless of status of the wait
         SDL_assert(mutex->count == 0 && mutex->owner == 0);
···
 
         SDL_assert(SDL_mutex_impl_active.Type == SDL_MUTEX_CS);
 
-        result = pSleepConditionVariableCS(&cond->cond, &mutex->cs, timeout);
+        result = (pSleepConditionVariableCS(&cond->cond, &mutex->cs, timeout) == TRUE);
     }
 
     return result;

src/thread/windows/SDL_sysmutex.c

···
 static bool SDL_TryLockMutex_cs(SDL_Mutex *mutex_)
 {
     SDL_mutex_cs *mutex = (SDL_mutex_cs *)mutex_;
-    return TryEnterCriticalSection(&mutex->cs);
+    return (TryEnterCriticalSection(&mutex->cs) == TRUE);
 }
 
 static void SDL_UnlockMutex_cs(SDL_Mutex *mutex_) SDL_NO_THREAD_SAFETY_ANALYSIS  // clang doesn't know about NULL mutexes