petsc: add 64bit variant (#2655)

* petsc: add 64bit variant

* hypre: add int64 variant

* superlu-dist: add int64 variant

* petsc: add int64 variant

* metis: rename idx64 to int64 to make it consistent with other packages

* mumps: rename idx64 to int64 to make it consistent with other packages

* dealii: rename 64bit to int64 to make it consistent with other packages

var/spack/repos/builtin/packages/hypre/package.py

@@ -46,6 +46,8 @@ class Hypre(Package):
     # SuperluDist have conflicting headers with those in Hypre
     variant('internal-superlu', default=True,
             description="Use internal Superlu routines")
+    variant('int64', default=False,
+            description="Use 64bit integers")
 
     depends_on("mpi")
     depends_on("blas")
@@ -68,6 +70,9 @@ def install(self, spec, prefix):
             '--with-blas-lib-dirs=%s' % ' '.join(blas.directories)
         ]
 
+        if '+int64' in self.spec:
+            configure_args.append('--enable-bigint')
+
         if '+shared' in self.spec:
             configure_args.append("--enable-shared")