patch to allow gerris to use hypre without mpi

--- a/configure.ac
+++ b/configure.ac
@@ -336,7 +336,7 @@
 
 # Build hypre module if HYPRE is installed
 hypre=no
-if test "x$use_mpicc" = "xyes" ; then # HYPRE needs MPI
+# hypre does not need mpi
    AC_CHECK_LIB(HYPRE, HYPRE_IJMatrixCreate, hypre="yes", hypre="no", [-lm])
    if test x$hypre = xyes; then
       AC_CHECK_HEADERS(HYPRE.h, hypre="yes", hypre="no")
@@ -344,7 +344,7 @@
    if test x$hypre = xno; then
       AC_MSG_WARN([HYPRE not found. hypre Module won't be available.])
    fi
-fi
+
 AM_CONDITIONAL(BUILD_HYPRE, test x$hypre = xyes)
 
 # Build lis module if lis is installed