Add kdialog support for KDE.

packaging/linux/AppRun.in

@@ -18,6 +18,8 @@ if mono_missing_or_old; then
   ERROR_MESSAGE="{MODNAME} requires Mono ${MINIMUM_MONO_VERSION} or greater.\nPlease install Mono using your system package manager."
   if command -v zenity > /dev/null; then
     zenity --no-wrap --error --title "{MODNAME}" --text "${ERROR_MESSAGE}" 2> /dev/null
+  elif command -v kdialog > /dev/null; then
+    kdialog --title "{MODNAME}" --error "${ERROR_MESSAGE}"
   else
     printf "${ERROR_MESSAGE}"
   fi

packaging/linux/openra.appimage.in

@@ -42,6 +42,8 @@ if [ $? != 0 ] && [ $? != 1 ]; then
   ERROR_MESSAGE="{MODNAME} has encountered a fatal error.\nPlease refer to the crash logs and FAQ for more information.\n\nLog files are located in ~/.openra/Logs\nThe FAQ is available at http://wiki.openra.net/FAQ"
   if command -v zenity > /dev/null; then
     zenity --no-wrap --error --title "{MODNAME}" --text "${ERROR_MESSAGE}" 2> /dev/null
+  elif command -v kdialog > /dev/null; then
+    kdialog --title "{MODNAME}" --error "${ERROR_MESSAGE}"
   else
     printf "${ERROR_MESSAGE}\n"
   fi

packaging/linux/openra.in

@@ -16,6 +16,8 @@ if [ $? != 0 ] && [ $? != 1 ]; then
   ERROR_MESSAGE="{MODNAME} has encountered a fatal error.\nPlease refer to the crash logs and FAQ for more information.\n\nLog files are located in ~/.openra/Logs\nThe FAQ is available at http://wiki.openra.net/FAQ"
   if command -v zenity > /dev/null; then
     zenity --no-wrap --error --title "{MODNAME}" --text "${ERROR_MESSAGE}" 2> /dev/null
+  elif command -v kdialog > /dev/null; then
+    kdialog --title "{MODNAME}" --error "${ERROR_MESSAGE}"
   else
     printf "${ERROR_MESSAGE}\n"
   fi