Add preliminary build glue to include AGMG in the OPM-Core library.

The approach will likely be changed due to the presence of
"subdir-objects" in the AM_INIT_AUTOMAKE call.

Makefile.am

@@ -271,3 +271,13 @@ opm/core/linalg/LinearSolverIstl.cpp
 nobase_include_HEADERS +=			\
 opm/core/linalg/LinearSolverIstl.hpp
 endif
+
+
+if BUILD_AGMG
+libopmcore_la_SOURCES +=			\
+$(AGMG_SRCDIR)/dagmg.f90			\
+$(AGMG_SRCDIR)/dagmg_mumps.f90
+
+libopmcore_la_LDFLAGS +=			\
+$(FCLIBS)
+endif

configure.ac

@@ -42,6 +42,7 @@ AX_BOOST_FILESYSTEM
 AX_BOOST_UNIT_TEST_FRAMEWORK
 
 AX_DUNE_ISTL
+OPM_AGMG
 
 # Checks for header files.
 AC_CHECK_HEADERS([float.h limits.h stddef.h stdlib.h string.h])

m4/agmg.m4

@@ -0,0 +1,29 @@
+AC_DEFUN([OPM_F90_COMPILATION_SYSTEM],
+[AC_REQUIRE([AC_PROG_FC_C_O])dnl
+ AC_REQUIRE([AC_FC_WRAPPERS])dnl
+ AC_REQUIRE([AC_FC_LIBRARY_LDFLAGS])dnl
+])[]dnl
+
+AC_DEFUN([OPM_AGMG],dnl
+[AC_ARG_WITH([agmg],dnl
+ [AS_HELP_STRING([--with-agmg=SRCDIR],dnl
+  [Include DOUBLE PRECISION version Notay's of AGMG Algebraic
+   Multigrid solver from specified source location SRCDIR. Note: this
+   option requires a complete, working Fortran 90 environment.])],
+ [],dnl
+ [with_agmg=no])[]dnl
+
+ AS_IF([test x"$with_agmg" != x"no" -a -d "$with_agmg"],dnl
+ [AS_IF([test -f "$with_agmg/dagmg.f90"],dnl
+  [AC_SUBST([AGMG_SRCDIR], [$with_agmg])[]dnl
+   AC_DEFINE([HAVE_AGMG], [1],dnl
+             [Define to `1' if Notay's AGMG solver is included])[]dnl
+   build_agmg="yes"],dnl
+  [build_agmg="no"])],dnl
+ [build_agmg="no"])[]dnl
+
+ AS_IF([test x"$build_agmg" = x"yes"],dnl
+   [AC_REQUIRE([OPM_F90_COMPILATION_SYSTEM])], [:])[]dnl
+
+ AM_CONDITIONAL([BUILD_AGMG], [test x"$build_agmg" = x"yes"])
+])[]dnl