bug#35863: `guix import hackage random` fails due to mysterious CRLF-related trouble

[Robert Vollmert]

$ curl http://hackage.haskell.org/package/random-1.1/random.cabal > random.cabal
$ guix import hackage -s < random.cabal
 (at line 49, column 0)d token : 
Syntax error: unexpected end of input
guix import: error: failed to import cabal file from standard input
$ tr -d '\r'  < random.cabal | guix import hackage -s
(package …)

There’s nothing obviously wrong in the cabal file around line 49. The file seems
to have consistent CRLF line endings and doesn’t seem to have any non-ASCII
characters. (I can see that `canonical-newline-port` might well be buggy around
UTF8.)