Addresses #486 and takes into account @rustyrussell 's
comment about PYTEST defined in the environment which
always overrides without checking the version.
You can use environment variables or the commandline to set defaults.
It looks very autoconf, but you don't need to learn m4.
Doesn't cover all the obscure flags, but it's easy to extend.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Jan Sarenik
Rusty Russell
Christian Decker