cmake-gui: Store last used generator platform and generator toolset

Status Job ID Name Coverage
  External
passed cdash

passed cmake-dash3win7-windows-release-ninja

00:27:01

passed cmake-hythloth-linux-debug-makefiles+sphinx

00:47:40

passed cmake-minoc-linux-release-lint-iwyu-tidy

00:10:49

passed cmake-moonshade-osx-debug-ninja

00:10:45

passed cmake-moonshade-osx-release-makefiles

00:12:16

passed cmake-terfin-windows-release-vs2019

00:42:34

passed ghostflow-check-master