Added integer-simple flag.

This allows the library to build with GHC versions using the
integer-simple library instead of integer-gmp.

I think this should resolve issues swamp-agr#1 and swamp-agr#8.

Blaze/Text/Int.hs

@@ -30,11 +30,15 @@ import GHC.Types (Int(..))
 # if __GLASGOW_HASKELL__ < 611
 import GHC.Integer.Internals
 # else
-import GHC.Integer.GMP.Internals
+#ifdef INTEGER_GMP
+import           GHC.Integer.GMP.Internals
+#elseif defined (INTEGER_SIMPLE)
+import           GHC.Integer.Simple.Internals
+#endif
 # endif
 #endif
 
-#ifdef INTEGER_GMP
+#if defined (INTEGER_GMP) || defined (INTEGER_SIMPLE)
 # define PAIR(a,b) (# a,b #)
 #else
 # define PAIR(a,b) (a,b)
@@ -106,7 +110,9 @@ int = integral
 {-# INLINE int #-}
 
 integer :: Integer -> Builder
+#ifdef INTEGER_GMP
 integer (S# i#) = int (I# i#)
+#endif
 integer i
     | i < 0     = minus `mappend` go (-i)
     | otherwise = go i

blaze-textual.cabal

@@ -35,6 +35,11 @@ flag native
   default: True
   manual: True
 
+flag integer-simple
+  description: use integer-simple instead of integer-gmp
+  default: False
+  manual: True
+
 library
   exposed-modules:
     Blaze.Text
@@ -67,13 +72,18 @@ library
 
   ghc-options:      -Wall
 
-  if impl(ghc >= 6.11)
-    cpp-options: -DINTEGER_GMP
-    build-depends: integer-gmp >= 0.2
+  if flag(integer-simple) && impl(ghc >= 6.12.1)
+    cpp-options: -DINTEGER_SIMPLE
+    build-depends: integer-simple
+
+  else
+    if impl(ghc >= 6.11)
+      cpp-options: -DINTEGER_GMP
+      build-depends: integer-gmp >= 0.2
 
-  if impl(ghc >= 6.9) && impl(ghc < 6.11)
-    cpp-options: -DINTEGER_GMP
-    build-depends: integer >= 0.1 && < 0.2
+    if impl(ghc >= 6.9) && impl(ghc < 6.11)
+      cpp-options: -DINTEGER_GMP
+      build-depends: integer >= 0.1 && < 0.2
 
 test-suite tests
   type:           exitcode-stdio-1.0