Changed QT_QPA_PLATFORM to a warning instead of an overwrite, also changed default order of plugins to offscreen then xcb, this has the effect of trying xcb first then offscreen it should just transparently do the right thing according to my testing

Signed-off-by: Ethan Mahintorabi <ethanmoon@google.com>

Author: QuantamHD

MODULE.bazel

@@ -108,7 +108,7 @@ bazel_dep(name = "zlib", version = "1.3.1.bcr.5")
 bazel_dep(name = "qt-bazel")
 git_override(
     module_name = "qt-bazel",
-    commit = "cb23dbb95bf772b5cc1aabf58b1986c34ba35d74",
+    commit = "75fcc653ef391612d64ca3071cd927c878f69f2e",
     remote = "https://github.com/The-OpenROAD-Project/qt_bazel_prebuilts",
 )
 

src/gui/src/gui.cpp

@@ -1542,7 +1542,18 @@ int startGui(int& argc,
              bool minimize)
 {
 #ifdef STATIC_QPA_PLUGIN_XCB
-  setenv("QT_QPA_PLATFORM", "xcb", /*__replace=*/true);
+  const char* qt_qpa_platform_env = getenv("QT_QPA_PLATFORM");
+  std::string qpa_platform
+      = qt_qpa_platform_env == nullptr ? "" : qt_qpa_platform_env;
+  if (qpa_platform != "") {
+    if (qpa_platform.find("xcb") == std::string::npos
+        && qpa_platform.find("offscreen") == std::string::npos) {
+      // OpenROAD logger is not available yet, using cout.
+      std::cout << "Your system has set QT_QPA_PLATFORM='" << qpa_platform
+                << "', openroad only supports 'offscreen' and 'xcb', please "
+                   "include one of these plugins in your platform env\n";
+    }
+  }
 #endif
   auto gui = gui::Gui::get();
   // ensure continue after close is false