90% of a fix for issue #40.

1 files changed, 18 insertions, 0 deletions

diff --git a/cffi/ffiplatform.py b/cffi/ffiplatform.py
index b3eef21..19cabf6 100644
--- a/cffi/ffiplatform.py
+++ b/cffi/ffiplatform.py
@@ -58,3 +58,21 @@ try:
 except ImportError:
     def samefile(f1, f2):
         return os.path.abspath(f1) == os.path.abspath(f2)
+
+def maybe_relative_path(path):
+    if not os.path.isabs(path):
+        return path      # already relative
+    dir = path
+    names = []
+    while True:
+        prevdir = dir
+        dir, name = os.path.split(prevdir)
+        if dir == prevdir or not dir:
+            return path     # failed to make it relative
+        names.append(name)
+        try:
+            if samefile(dir, os.curdir):
+                names.reverse()
+                return os.path.join(*names)
+        except OSError:
+            pass