Use C99 bool internally in SDL

src/power/emscripten/SDL_syspower.c

@@ -25,13 +25,13 @@
 
 #include <emscripten/html5.h>
 
-SDL_bool SDL_GetPowerInfo_Emscripten(SDL_PowerState *state, int *seconds, int *percent)
+bool SDL_GetPowerInfo_Emscripten(SDL_PowerState *state, int *seconds, int *percent)
 {
     EmscriptenBatteryEvent batteryState;
     int haveBattery = 0;
 
     if (emscripten_get_battery_status(&batteryState) == EMSCRIPTEN_RESULT_NOT_SUPPORTED) {
-        return SDL_FALSE;
+        return false;
     }
 
     haveBattery = batteryState.level != 1.0 || !batteryState.charging || batteryState.chargingTime != 0.0;
@@ -40,7 +40,7 @@ SDL_bool SDL_GetPowerInfo_Emscripten(SDL_PowerState *state, int *seconds, int *p
         *state = SDL_POWERSTATE_NO_BATTERY;
         *seconds = -1;
         *percent = -1;
-        return SDL_TRUE;
+        return true;
     }
 
     if (batteryState.charging) {
@@ -52,7 +52,7 @@ SDL_bool SDL_GetPowerInfo_Emscripten(SDL_PowerState *state, int *seconds, int *p
     *seconds = (int)batteryState.dischargingTime;
     *percent = (int)batteryState.level * 100;
 
-    return SDL_TRUE;
+    return true;
 }
 
 #endif // SDL_POWER_EMSCRIPTEN