Now that Bug 215450 has landed on mozilla-central we are broken.
/builds/slave/comm-cen-trunk-lnx/build/mailnews/base/src/nsMessenger.cpp: In member function ‘virtual nsresult nsSaveMsgListener::OnDataAvailable(nsIRequest*, nsISupports*, nsIInputStream*, PRUint32, PRUint32)’:
/builds/slave/comm-cen-trunk-lnx/build/mailnews/base/src/nsMessenger.cpp:1908:40: error: no matching function for call to ‘nsIInputStream::Available(PRUint32*)’
../../../mozilla/dist/include/nsIInputStream.h:66:60: note: candidate is: virtual nsresult nsIInputStream::Available(PRUint64*)
NEXT ERROR make: *** [nsMessenger.o] Error 1
There is a patch already waiting for review over in bug 215450
*** Bug 782255 has been marked as a duplicate of this bug. ***
This has hopefully been fixed by bug 215450. I'll check on the trees in the morning and re-open if they go green.