Fix installs-deps -a catch2 issue on ubuntu 20.04#516

Merged

jw-msft merged 3 commits intodevelopfrom user/jw-msft/fix2004instdeps

Aug 11, 2023

+20-6

Commits on Aug 10, 2023

install gcc-10 on ubuntu 20.04 for -a to fix catch2 selftest unknown option error -Wcomma-subscript
jw-msft
committed
force catch2 to use the ver of gcc/g++
jw-msft
committed

Commits on Aug 11, 2023

set CC and CXX on cmake cmdline instead of exporting
jw-msft
committed