use warnings;
use strict;

my $buildlog = 'fred.txt';

open (my $pipe, '-|', 
      'nmake -f  TEST.mak CFG="TEST - Win32 Solaris_Release" 2>&1') ||
      die "Unable to run nmake: $!";

open(my $log, '>', $buildlog) || die "Can't open $buildlog: $!";

while (<$pipe>) {
   print;
   print $log $_;
}

close ($pipe); 
close ($log);

my $status = $?;
...