Bug#1139536: hypre: FTBFS: HYPRE_utilities.h:20:10: fatal error: mpi.h: No such file or directory

[Graham Inggs]

This may be related to the following change in debhelper 13.32.  See
also #1139889 [1].

 [ Helmut Grohne ]
 * autoconf: export standard build tools


[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1139889