Describe signature mini-backpack.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Add more primops for atomic ops on byte arrays

Summary:
Add more primops for atomic ops on byte arrays

Adds the following primops:

 * atomicReadIntArray#
 * atomicWriteIntArray#
 * fetchSubIntArray#
 * fetchOrIntArray#
 * fetchXorIntArray#
 * fetchAndIntArray#

Makes these pre-existing out-of-line primops inline:

 * fetchAddIntArray#
 * casIntArray#
Fixup c1035d51e to behave more like in GHC 7.6

The fix in c1035d51e (addressing #9231) was done under the assumption
that `Data.Fixed` is used only with power-of-10 `resolution`. This
follow-up fixup changes the behavior to be more consistent with the
previous behavior in GHC 7.6

For instance, for the following `B7` resolution

   > data B7
   > instance HasResolution B7 where resolution _ = 128

After this patch, the following behavior is now observable:

   > 1.070 :: Fixed B7
   1.062
   > 1.062 :: Fixed B7
   1.054

   > read "1.070" :: Fixed B7
   1.062
   > read "1.062" :: Fixed B7
   1.054

This doesn't provide the desirable "read . show == id" property
yet (which didn't hold in GHC 7.6 either), but at least `fromRational`
and `read` are consistent.

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Convert loose sub-repos into proper submodules (re #8545)

Specifically, the following sub-repos/modules are converted:

 - libffi-tarballs
 - libraries/array
 - libraries/deepseq
 - libraries/directory
 - libraries/dph
 - libraries/filepath
 - libraries/haskell2010
 - libraries/haskell98
 - libraries/hoopl
 - libraries/hpc
 - libraries/old-locale
 - libraries/old-time
 - libraries/parallel
 - libraries/process
 - libraries/stm
 - libraries/unix
 - nofib
 - utils/hsc2hs

N.B. ghc-tarballs is not converted as it will probably be handled
     differently in the future.

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Typos in comments
Fix anchors in Haddock

Updates submodule
Fix few Haddock parser brainfarts

Updates submodule
The linking restriction, no shaping necessary.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Merge latest changes from upstream

Among other latest changes, this commit converts some formerly separate
repositories into git submodules.