Retry to open the clipboard in case another application has it open

This fixes 'testautomation --filter clipboard_testClipboardTextFunctions' on Windows

src/video/windows/SDL_windowsclipboard.c

@@ -102,23 +102,31 @@ int WIN_SetClipboardText(SDL_VideoDevice *_this, const char *text)
 
 char *WIN_GetClipboardText(SDL_VideoDevice *_this)
 {
-    char *text;
-
-    text = NULL;
-    if (IsClipboardFormatAvailable(TEXT_FORMAT) &&
-        OpenClipboard(GetWindowHandle(_this))) {
-        HANDLE hMem;
-        LPTSTR tstr;
-
-        hMem = GetClipboardData(TEXT_FORMAT);
-        if (hMem) {
-            tstr = (LPTSTR)GlobalLock(hMem);
-            text = WIN_StringToUTF8(tstr);
-            GlobalUnlock(hMem);
-        } else {
-            WIN_SetError("Couldn't get clipboard data");
+    char *text = NULL;
+
+    if (IsClipboardFormatAvailable(TEXT_FORMAT)) {
+        /* Retry to open the clipboard in case another application has it open */
+        const int MAX_ATTEMPTS = 3;
+        int attempt;
+
+        for (attempt = 0; attempt < MAX_ATTEMPTS; ++attempt) {
+            if (OpenClipboard(GetWindowHandle(_this))) {
+                HANDLE hMem;
+                LPTSTR tstr;
+
+                hMem = GetClipboardData(TEXT_FORMAT);
+                if (hMem) {
+                    tstr = (LPTSTR)GlobalLock(hMem);
+                    text = WIN_StringToUTF8(tstr);
+                    GlobalUnlock(hMem);
+                } else {
+                    WIN_SetError("Couldn't get clipboard data");
+                }
+                CloseClipboard();
+                break;
+            }
+            SDL_Delay(10);
         }
-        CloseClipboard();
     }
     if (text == NULL) {
         text = SDL_strdup("");