Fix FTBFS with -qt-sql-sqlite3

Fix FTBFS when sqlite3 sql driver is being built into the library

Signed-off-by: Alexander Golubev <fatzer2@gmail.com>

src/sql/qt_sql.pri

@@ -255,6 +255,11 @@ sql {
             HEADERS += $$SQL_CPP/drivers/sqlite3/qsql_sqlite3.h
             SOURCES += $$SQL_CPP/drivers/sqlite3/qsql_sqlite3.cpp
             DEFINES += QT_SQL_SQLITE3
+            unix {
+                !contains( LIBS, .*sqlite3.* ) {
+                    LIBS *= -lsqlite3
+                }
+            }
         }
 }