[Coco] Drive letter issue in paths with toolshed os9 copy command on Windows

[Guillaume Major]

Hi all!

I'm currently writing some batch files on Windows to automate the process of 
building OS-9 disk images. I use toolshed's os9 command to copy the files on 
the disk images. The command works as expected except when I include the 
drive letter in absolute paths. Example:

os9 format sq1-becker.dsk
os9 copy Startup sq1-becker.dsk,Startup        <-- works

os9 format sq1-becker.dsk
os9 copy Startup c:\coco\sq1-becker.dsk,Startup        <-- fails with error 
248: disk is filled to capacity

Digging in the source code, I found out that when the path contains a colon, 
the disk is identified as a DECB disk without looking at the disk file 
content (step 2a in function _coco_identify_image in libcoco/libcocoopen.c). 
While it works well on Linux, it prevents using drive letters in paths on 
Windows.

I compiled toolshed on my Windows machine with the latest source code. If I 
comment out step 2a in _coco_identify_image, the disk image is successfully 
identified as an OS9 disk and the command works as expected.

My question is for the toolshed gurus: can this step be removed (at least 
for Windows) for identifying the disk/cassette image?

Thanks,
Guillaume