prereq-build: add additional git detection

prereq-build: add additional git detection

With some OS (Guix) the git submodule command is wrapped in
a script. Current logic parse the git submodule script directly.
If it's wrapped the prereq check wrongly fails while 'git submodule
--recursive' is actually available.
Add an additional check that try to directly use the 'git submodule'
command to check if the prereq is satisfied.

Fixes: #9986
Reported-by: Attila Lendvai <[email protected]>
Suggested-by: Attila Lendvai <[email protected]>
Signed-off-by: Christian 'Ansuel' Marangi <[email protected]>