Drop redundant/obsolete pragmas

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
`M-x untabify` & `M-x delete-trailing-whitespaces`

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Update aux files `config.{guess,sub}` and `install-sh`

This updates the files to the versions bundled with GNU automake 1.13.3

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Refactor & modernize `hpc.cabal` to `cabal-version>=1.10`

This restricts the `build-depend` to GHC HEAD/7.8's library versions, as
the current `old-time` code effectively fails to compile on older
GHCs (with their older `base` library).

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>