Detect when Sage is build on AFS and issue a warning

[mabshoff]

From  http://groups.google.com/group/sage-devel/t/894d29e0bde4550c

> Yes, afs is a strange filessystem and might be the root cause of your 
> trouble, but that is far from certain at this point. 


No longer far from certain. The build completed without ANY problems, 
including getting past gnutls without error. This is not unprecedented 
but somewhat surprising nevertheless. Running make test now. 

Gedaliah 

AFS seems to be commonly used with RHEL 4 in some instituations. It has come up twice now.

Cheers,

Michael

[mabshoff]

Gedaliah responded to my question:

> In case you have a shell code snipped that identifies that the current 
> working directory is on an AFS mount I would be happy to integrate it. 


This will work unless somebody very foolishly changed the afs mount 
point to something other that /afs. 
[[ $(pwd | cut -d'/' -f2) = 'afs' ]] && echo "we are in afs" 

Cheers,

Michael

[wjp]

Should anyone want to do this, Sun's struct stat has a st_fstype field which gives the filesystem type of a file, so from C this might be easy to check.