We don't commit *.o files anywhere, not even as test data. So ignore them
everywhere.
This resolves *.o files not being ignored under 3rdparty/p256-m.
Also remove a redundant ignore of *.exe in a subdirectory.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Having an automatically generated header file makes it harder to have
working build scripts. The content of ssl_debug_helpers_generated.h isn't
likely to change often, so we can update it manually.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>