Check for valid QT versions or bail early

build.sh

@@ -30,7 +30,21 @@ then
 fi
 
 VERSION=$(grep APP_VERSION src/version.h |cut -d\" -f2)
-echo "Compiling SilentDragonLite $VERSION on $UNAME with args=$@"
+QTVERSION=$(qmake --version | tail -n 1 | cut -d' ' -f4)
+QT_MAJOR_VERSION=$(echo $QTVERSION | cut -d. -f1)
+QT_SUB_VERSION=$(echo $QTVERSION | cut -d. -f2)
+
+if [ "$QT_MAJOR_VERSION" != "5" ]; then
+    echo "Your QT version $QTVERSION is not compatible, only QT 5.x is supported"
+    exit 1
+fi
+
+if [ "$QT_SUB_VERSION" -lt "12" ]; then
+    echo "Your QT version $QTVERSION is not compatible, at least QT 5.12.0 is required"
+    exit 1
+fi
+
+echo "Compiling SilentDragonLite $VERSION on $UNAME with QT $QTVERSION and args=$@"
 CONF=silentdragon-lite.pro
 
 set -e