Revert "Disable xcb_xlib"

This reverts commit d1ff6e583d.

Otherwise HIME input is broken:
https://github.com/telegramdesktop/tdesktop/issues/26228

Telegram/SourceFiles/platform/linux/specific_linux.cpp

@@ -50,20 +50,12 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <unistd.h>
 #include <dirent.h>
 #include <pwd.h>
-#include <dlfcn.h>
 
 #include <iostream>
 
 using namespace Platform;
 using Platform::internal::WaylandIntegration;
 
-#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
-typedef struct _XDisplay Display;
-struct XErrorEvent;
-typedef int (*XErrorHandler)(Display*, XErrorEvent*);
-typedef XErrorHandler (*LPXSETERRORHANDLER)(XErrorHandler);
-#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION
-
 typedef GApplication TDesktopApplication;
 typedef GApplicationClass TDesktopApplicationClass;
 
@@ -840,20 +832,6 @@ void start() {
 			"except various functionality to not to work.");
 	}
 
-#ifndef DESKTOP_APP_DISABLE_X11_INTEGRATION
-	// tdesktop doesn't use xlib by itself,
-	// but some libraries it depends on may do
-	const auto XSetErrorHandler = reinterpret_cast<LPXSETERRORHANDLER>(
-		dlsym(RTLD_DEFAULT, "XSetErrorHandler"));
-
-	// Reset errors if any
-	(void) dlerror();
-
-	if (XSetErrorHandler) {
-		XSetErrorHandler([](Display *dpy, XErrorEvent *err) { return 0; });
-	}
-#endif // !DESKTOP_APP_DISABLE_X11_INTEGRATION
-
 	InstallLauncher();
 	LaunchGApplication();
 }

Telegram/build/docker/centos_env/Dockerfile

@@ -744,7 +744,6 @@ RUN git clone -b {{ QT_TAG }} --depth=1 https://code.qt.io/qt/qt5.git qt_{{ QT }
 		-qt-harfbuzz \
 		-qt-pcre \
 		-no-icu \
-		-no-feature-xcb-xlib \
 		-no-feature-xcb-sm \
 		-no-feature-egl-extension-platform-wayland \
 		-static \