Process output of a simple command

[Dr. David Kirkby]

When autoconf runs on a Solaris machine, config.log shows:
---------------------------------
## --------- ##
## Platform. ##
## --------- ##

hostname = swan
uname -m = sun4u
uname -r = 5.10
uname -s = SunOS
uname -v = Generic_139555-08

/usr/bin/uname -p = sparc
/bin/uname -X     = System = SunOS
Node = swan
Release = 5.10
KernelID = Generic_139555-08
Machine = sun4u
BusType = <unknown>
Serial = <unknown>
Users = <unknown>
OEM# = 0
Origin# = 1
NumCPU = 2

/bin/arch              = sun4
/usr/bin/arch -k       = sun4u
/usr/convex/getsysinfo = unknown
address@hidden:[~/sage-4.1.2.rc2/spkg/base/prereq-0.5] $ grep sun4u config.log
uname -m = sun4u
Machine = sun4u
---------------------------

How can I get that result of 'Machine' or '/usr/bin/arch -k' and use it in 
configure.ac ?

If someone runs on Solaris 9 or earlier, I'd like to tell them to upgrade to 
Solaris 10, but if they are using 'sun4m' machines, then that is impossible for 
them. Likewise, if they are using sun4v machines, I'd like to bring to their 
attention a bug in Solaris, and how to circumvent it.

I tried:

if test x$Machine = 'xsun4m'
then
  AC_MSG_WARN([This is a sun4m computer running Solaris])
  etc etc
fi

but that does not work.


dave