ZipFile builder src_dir argument does not seem to work as expected

[Marc Valle]

The Zipfile builder seems to cut off the number of characters in src_dir parameter in the target zip.

I am currently working around it using the following code, but I wonder if this is intended.

dist_files = Pattern(somefiles)
env['SDK_NO_PKG'] = '$SDK_ROOT/{0}'.format(distname)

distout = env.SdkNoPkg(dist_files)
# the following is a bit of a HACK. The Zipfile builder seems to
# cut off the number of characters in src_dir parameter in the
# target zip.  We leverage that behavior here to remove leading
# parts of _sdks path so we just end up with a dist with 
# distdir as root. This will need update if this parts bug gets
# fixed.
dist_zip = env.ZipFile(distname, distout, src_dir='$SDK_ROOT')
env.Depends(dist_zip, versionfile)

env.PkgNoInstall(dist_zip)

It actually doesn't matter what the src_dir characters are as long as the length of the string is the same as the the length of SDK_ROOT. This seems like a bug, or I don't understand this API (which is possible, I could find no documentation on this)