...so better make it std::atomic<> (and it also can be private).  And in
SolarMutex::doRelease, make sure that m_nCount is only read with m_aMutex
locked.

Change-Id: Iee0c1465e60e07ccd8955010a3dbc15a99dbe807
Reviewed-on: https://gerrit.libreoffice.org/71260
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>