...as flagged with -Werror=deprecated by trunk GCC in -std=c++2a mode.  But
C++17 forbids "this" in combination with a capture-default of "=", so in such
cases list any entities explicitly that shall be captured by value.

Change-Id: Ic228cd20682277a0f93e3e75798356d0fbbb80d4
Reviewed-on: https://gerrit.libreoffice.org/65241
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>