[give nicer error message on jhc --show-ho foo
David Roundy <roundyd@physics.oregonstate.edu>**20090902162143
 Ignore-this: 187d8cf167aa67786882e458400edc2b20c4a6db
] hunk ./src/Ho/Build.hs 808
+            _ -> putErrDie "Error: --show-ho requires a .hl or .ho file"