diff --git a/waflib/ansiterm.py b/waflib/ansiterm.py
index 3c429d9f..28add846 100644
--- a/waflib/ansiterm.py
+++ b/waflib/ansiterm.py
@@ -11,7 +11,7 @@ console commands.
 
 """
 
-import re, sys
+import os, re, sys
 from waflib.Utils import threading
 
 wlock = threading.Lock()
@@ -329,7 +329,7 @@ try:
 except ImportError:
 	pass
 else:
-	if sys.stdout.isatty() or sys.stderr.isatty():
+	if (sys.stdout.isatty() or sys.stderr.isatty()) and os.environ.get('TERM', '') not in ('dumb', 'emacs'):
 		FD = sys.stdout.isatty() and sys.stdout.fileno() or sys.stderr.fileno()
 		def fun():
 			return struct.unpack("HHHH", fcntl.ioctl(FD, termios.TIOCGWINSZ, struct.pack("HHHH", 0, 0, 0, 0)))[1]