Compatibility with GHC 7.7
catching up to the latest GHC 7.7.
unquoting unicode quote for GHC 7.7 or later.
fixing a test for GHC 7.7 by using Unicode quote.
using #ifdef for quote.
Importing System.SetEnv according to the version of "base".
GHC 7.7 uses both quotations.
Merge branch 'ghc-7.7'

Note on "cabal test doctests": this test fails. But the source of this bug is clear. When if "doctest" calls "doctest", this bug appears. Removing examples from "doctest" in src/Run.hs results in the success of this test. I don't know why but "v_opt_C_ready" is set True in GHC 7.7 just before running examples.

We need to specify "--enable-dynamic" to "cabal" when testing with GHC 7.7.

Note on "cabal test spec": only few test cases fail.