omnetpp: on WSL force the IDE and Qtenv to use the x11 backend instea…

…d of wayland

The wayland backend still has some issues:

- missing runtime icon (displayed on the taskbar)
- resizing panels in the IDE does not show a cursor change when hovering over the handle
- missing minimize/maximize buttons

Once these are worked out, this can be reverted to default to wayland backend
Right now, Qtenv defaults to x11 while the IDE defaulted to wayland

opp_env/database/omnetpp.py

@@ -270,6 +270,9 @@ def make_omnetpp_project_description(version, base_version=None, is_modernized=F
             "export PATH=$(pwd)/bin:$PATH && export LD_LIBRARY_PATH=$(pwd)/lib:$LD_LIBRARY_PATH && export TCL_LIBRARY=$(echo 'puts [info library]; exit' | wish)" if version == "3.3.1" else
             "source setenv" + (" -f" if base_version.startswith("5.") else ""), # -f allows setenv to be called from scripts
 
+            # force the use of xwayland on WSL as running with wayland has some issues (missing runtime icons, non working cursor changes, etc.)
+            """if grep -qEi "microsoft" /proc/sys/kernel/osrelease; then export GDK_BACKEND="x11"; export QT_QPA_PLATFORM="xcb";fi """ if is_linux else ""  
+
             # export which opp_run bin to use depending on omnetpp version
             # before 5.2.0, opp_run was debug, and opp_run_release was release
             # INET versions before 4.0 need the opp_run bin for running smoke tests; some INET versions work (e.g. 3.6.1) work with both omnetpp 5.2.0 and 5.1.2