Handles making building world/kern a little more pleasant on the eyes, not done yet, only supports FreeBSD and doesn't log at the moment.

bbldr.py

#!/usr/bin/env python

import os, re, sys, time
import subprocess as SP

class oList(list):
  def join(self):
    retv = ''
    for i in self:
      retv += i+' '
    return retv

args = oList(sys.argv)
BN   = os.path.basename(sys.argv[0])
OS   = os.uname()[0]
LG   = open('/tmp/%s-build.log' % OS, 'w+')
args.pop(0)

if OS == 'FreeBSD' or OS == 'DragonflyBSD' or OS == 'OpenBSD': 
  cmd = 'make'
elif OS == 'NetBSD': cmd = '/usr/src/build.sh'
else:
  print 'You are on an unsupported platform.'
  sys.exit(1)

try:
  if args[0].find('help') != -1 or args[0] == '-h':
    print 'Usage: %s <make args for /usr/src>' % bname
    print 'Example: %s -j4 buildkernel KERNCONF=CUSTOM' % bname
    sys.exit(0)
except IndexError:
  print 'Usage: %s <make args for /usr/src>' % bname
  print 'Example: %s -j4 buildkernel KERNCONF=CUSTOM' % bname
  sys.exit(0)

os.chdir('/usr/src')
st_time = time.time()
proc = SP.Popen('%s %s' % (cmd, args.join()), bufsize=0, 
  stdout=SP.PIPE, stderr=SP.STDOUT, close_fds=False, shell=True)

tp_time = None
try:
  while 1:
    buf = proc.stdout.readline()
    if not buf:
      break
    LG.write(buf.strip())
    if buf.strip().find('>>> ') != -1:
      if buf.strip().find('stage') != -1:
        if tp_time == None:
          print buf.strip()+' '*20
          tp_time = time.time()
        else:
          tmp = time.time()
          print buf.strip()+' (Last step runtime: %.02f sec)%s' % ((tmp - tp_time), ' '*5)
          tp_time = tmp
      else: print buf.strip()+' '*25
    elif buf.strip().find('==> ') != -1 and buf.strip()[0] == '=':
      sys.stdout.write('%s%s\r' % (buf.strip(), ' '*25))
      sys.stdout.flush()
except OSError:
  print 'Something went horridly wrong.'
  sys.exit(-1)
    
proc.poll()
LG.flush()
LG.close()
if proc.returncode != None:
  print 'Total runtime: %d seconds.' % (time.time() - st_time)
else:
  print 'There was an error in the build, check /tmp/%s-build.log for details.' % OS