installation fails when using SU_CMD=su -...

[Klaus Heinz <k.heinz%febacht.kh-22.de@localhost>]

Hi,

I just noticed there is something wrong with SU_CMD: I cannot build
games/netmaj with "SU_CMD=sudo su - root -c" because the environment
variable OPSYS (among others, like HOST_OSTYPE, LOWER_OPSYS,
LOWER_OS_VERSION) is not known. 

Now that I searched for it, it looks like doc/pkgsrc.txt has recommended
"su root..." instead of "su - root..." since revision 1.1 from 2004.

Is my memory wrong when I think that "su - root..." has been supported
in the past?

ciao
     Klaus