fix arch on linux mint

[gronono]

I am using Linux Mint on a VirtualBox machine. And I got

$ uname
Linux vbl-abr-mint 3.19.0-32-generic #37~14.04.1-Ubuntu SMP Thu Oct 22 09:41:40 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
 $ uname -a
Linux vbl-abr-mint 3.19.0-32-generic #37~14.04.1-Ubuntu SMP Thu Oct 22 09:41:40 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
 $ uname -m
Linux vbl-abr-mint 3.19.0-32-generic #37~14.04.1-Ubuntu SMP Thu Oct 22 09:41:40 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

So I changed the MVN_ARCH detection to match on x86_64

[ljharb]

Does uname -m not work in Linux Mint?? I definitely do not want an unbounded wildcard comparison against the output of uname, who knows what else that could start matching.

[gronono]

I found my problem. I got an alias for uname to uname -a.
You can use \uname in the script to skip aliases

[ljharb]

@gronono ah, thanks - i'll fix that (although it's a very bad idea to alias over builtins)