1 files changed, 20 insertions, 5 deletions

diff --git a/xdelta3/setup.py b/xdelta3/setup.py
index 2fe3b19..ed1e1aa 100755
--- a/xdelta3/setup.py
+++ b/xdelta3/setup.py
@@ -17,19 +17,34 @@
 #
 #
 from distutils.core import setup, Extension
+from distutils.util import get_platform
+
+# External compression support works on Windows/Cygwin, but not from
+# within the Python module. It's something to do with fork() and
+# exec() support.
+platform  = get_platform()
+is_cygwin = platform.startswith('cygwin')
+extcomp   = 1
+
+if is_cygwin:
+    print 'Note: not compiling external compression support for Python/Cygwin'
+    extcomp = 0
+#end
 
 xdelta3_ext = Extension('xdelta3',
                         ['xdelta3.c'],
                         define_macros = [
-                                         ('REGRESSION_TEST',1),
+                                         ('PYTHON_MODULE',1),
                                          ('SECONDARY_DJW',1),
-                                         ('SECONDARY_FGK',1),
                                          ('VCDIFF_TOOLS',1),
-                                         ('XD3_DEBUG',1),
                                          ('XD3_POSIX',1),
-                                         ('EXTERNAL_COMPRESSION',1),
                                          ('XD3_USE_LARGEFILE64',1),
-                                         ('PYTHON_MODULE',1),
+
+                                         ('EXTERNAL_COMPRESSION',extcomp),
+
+                                         ('REGRESSION_TEST',0),
+                                         ('SECONDARY_FGK',0),
+                                         ('XD3_DEBUG',0),
                                          ],
                         extra_compile_args = [ '-O3',
                                                '-g',