CodeGeneration: Replace reference to isl_int with explicit mpz call.

This removes the last isl_int dependency in the default build. There are
still some in OpenScop and Scoplib. For those isl-0.12.2 still needs to be used.

llvm-svn: 199585
diff --git a/polly/lib/CodeGen/CodeGeneration.cpp b/polly/lib/CodeGen/CodeGeneration.cpp
index 75741d3..d98e7cf3 100644
--- a/polly/lib/CodeGen/CodeGeneration.cpp
+++ b/polly/lib/CodeGen/CodeGeneration.cpp
@@ -801,7 +801,7 @@
   int NumberOfIterations = polly::getNumberOfIterations(LoopDomain);
   if (NumberOfIterations == -1)
     return -1;
-  return NumberOfIterations / isl_int_get_si(For->stride) + 1;
+  return NumberOfIterations / mpz_get_si(For->stride) + 1;
 }
 
 void ClastStmtCodeGen::codegenForVector(const clast_for *F) {