Replaced a few single-line "//" comments.

src/audio/directsound/SDL_directsound.c

@@ -434,7 +434,6 @@ CreateCaptureBuffer(_THIS, const DWORD bufsize, WAVEFORMATEX *wfmt)
     LPDIRECTSOUNDCAPTURE capture = this->hidden->capture;
     LPDIRECTSOUNDCAPTUREBUFFER *capturebuf = &this->hidden->capturebuf;
     DSCBUFFERDESC format;
-//    DWORD junk, cursor;
     HRESULT result;
 
     SDL_zero(format);

src/core/linux/SDL_fcitx.c

@@ -506,7 +506,7 @@ SDL_Fcitx_UpdateTextRect(SDL_Rect *rect)
 #endif
 
     if (cursor->x == -1 && cursor->y == -1 && cursor->w == 0 && cursor->h == 0) {
-        // move to bottom left
+        /* move to bottom left */
         int w = 0, h = 0;
         SDL_GetWindowSize(focused_win, &w, &h);
         cursor->x = 0;

src/events/SDL_mouse.c

@@ -304,7 +304,7 @@ SDL_PrivateSendMouseMotion(SDL_Window * window, SDL_MouseID mouseID, int relativ
     if (window && ((window->flags & SDL_WINDOW_MOUSE_CAPTURE) == 0)) {
         int x_max = 0, y_max = 0;
 
-        // !!! FIXME: shouldn't this be (window) instead of (mouse->focus)?
+        /* !!! FIXME: shouldn't this be (window) instead of (mouse->focus)? */
         SDL_GetWindowSize(mouse->focus, &x_max, &y_max);
         --x_max;
         --y_max;

src/joystick/darwin/SDL_sysjoystick.c

@@ -609,8 +609,8 @@ SDL_SYS_JoystickDetect(void)
         }
     }
 
-	// run this after the checks above so we don't set device->removed and delete the device before
-	// SDL_SYS_JoystickUpdate can run to clean up the SDL_Joystick object that owns this device
+	/* run this after the checks above so we don't set device->removed and delete the device before
+	   SDL_SYS_JoystickUpdate can run to clean up the SDL_Joystick object that owns this device */
 	while (CFRunLoopRunInMode(SDL_JOYSTICK_RUNLOOP_MODE,0,TRUE) == kCFRunLoopRunHandledSource) {
 		/* no-op. Pending callbacks will fire in CFRunLoopRunInMode(). */
 	}

src/joystick/emscripten/SDL_sysjoystick.c

@@ -331,7 +331,7 @@ SDL_SYS_JoystickUpdate(SDL_Joystick * joystick)
 
                 for(i = 0; i < item->naxes; i++) {
                     if(item->axis[i] != gamepadState.axis[i]) {
-                        // do we need to do conversion?
+                        /* do we need to do conversion? */
                         SDL_PrivateJoystickAxis(item->joystick, i,
                                                   (Sint16) (32767.*gamepadState.axis[i]));
                     }

src/video/x11/SDL_x11modes.c

@@ -741,9 +741,9 @@ X11_InitModes(_THIS)
         displaydata->visual = vinfo.visual;
         displaydata->depth = vinfo.depth;
 
-        // We use the displaydata screen index here so that this works
-        // for both the Xinerama case, where we get the overall DPI,
-        // and the regular X11 screen info case.
+        /* We use the displaydata screen index here so that this works
+           for both the Xinerama case, where we get the overall DPI,
+           and the regular X11 screen info case. */
         displaydata->hdpi = (float)DisplayWidth(data->display, displaydata->screen) * 25.4f /
             DisplayWidthMM(data->display, displaydata->screen);
         displaydata->vdpi = (float)DisplayHeight(data->display, displaydata->screen) * 25.4f /