QMYSQLDriver - linking plugin's dynamic library

[ultr]

I'm trying to use QSqlDatabase::addDatabase() to access an already-open MySQL connection: http://doc.qt.nokia.com/latest/qsqldatabase.html#addDatabase-2

Documentation says to include driver's source file, which I don't want. It requires choosing a single version of Qt and may be acceptable for binary applications, but not for source distribution.

I tried including only the header file (QtSql/qsql_mysql.h) and linking the binary against plugins/sqldrivers/libqsqlmysql.so library (cmake):

[...]

find_library (QT_QSQLMYSQL_LIBRARY qsqlmysql)
if (QT_QSQLMYSQL_LIBRARY)
message (STATUS "Found QMYSQLDriver library: ${QT_QSQLMYSQL_LIBRARY}")
else (QT_QSQLMYSQL_LIBRARY)
message (FATAL_ERROR "Could not find QMYSQLDriver library")
endif (QT_QSQLMYSQL_LIBRARY)

target_link_libraries (sql_history ${QT_QTSQL_LIBRARIES} ${MYSQL_LIBRARIES} ${QT_QSQLMYSQL_LIBRARY})
but I still get linking error:

symbol lookup error: /.../libsql_history.so: undefined symbol: _ZN12QMYSQLDriverC1EP8st_mysqlP7QObject

Adding
#include <QtPlugin>
Q_IMPORT_PLUGIN(qsqlmysql)
results in another error:

undefined symbol: _Z28qt_plugin_instance_qsqlmysqlv)

Am I doing something wrong? How should this be done?