Linux: Use synchronous X11 error handling in debug builds

modules/juce_gui_basics/native/x11/juce_linux_X11_Symbols.cpp

@@ -181,6 +181,7 @@ bool X11Symbols::loadAllSymbols()
                        makeSymbolBinding (xSetWMNormalHints,           "XSetWMNormalHints"),
                        makeSymbolBinding (xStringListToTextProperty,   "XStringListToTextProperty"),
                        makeSymbolBinding (xSync,                       "XSync"),
+                       makeSymbolBinding (xSynchronize,                "XSynchronize"),
                        makeSymbolBinding (xTranslateCoordinates,       "XTranslateCoordinates"),
                        makeSymbolBinding (xrmUniqueQuark,              "XrmUniqueQuark"),
                        makeSymbolBinding (xUngrabPointer,              "XUngrabPointer"),

modules/juce_gui_basics/native/x11/juce_linux_X11_Symbols.h

@@ -453,6 +453,10 @@ public:
                                          (::Display*, Bool),
                                          void)
 
+    JUCE_GENERATE_FUNCTION_WITH_DEFAULT (XSynchronize, xSynchronize,
+                                         (::Display*, Bool),
+                                         int)
+
     JUCE_GENERATE_FUNCTION_WITH_DEFAULT (XTranslateCoordinates, xTranslateCoordinates,
                                          (::Display*, ::Window, ::Window, int, int, int*, int*, ::Window*),
                                          Bool)

modules/juce_gui_basics/native/x11/juce_linux_XWindowSystem.cpp

@@ -30,6 +30,10 @@ namespace juce
 
 #if JUCE_DEBUG && ! defined (JUCE_DEBUG_XERRORS)
  #define JUCE_DEBUG_XERRORS 1
+
+ #if ! defined (JUCE_DEBUG_XERRORS_SYNCHRONOUSLY)
+  #define JUCE_DEBUG_XERRORS_SYNCHRONOUSLY 1
+ #endif
 #endif
 
 #if JUCE_MODULE_AVAILABLE_juce_gui_extra
@@ -2719,6 +2723,10 @@ bool XWindowSystem::initialiseXDisplay()
     if (display == nullptr)
         return false;
 
+   #if JUCE_DEBUG_XERRORS_SYNCHRONOUSLY
+    X11Symbols::getInstance()->xSynchronize (display, True);
+   #endif
+
     // Create a context to store user data associated with Windows we create
     windowHandleXContext = (XContext) X11Symbols::getInstance()->xrmUniqueQuark();