Compatibility module for dunecontrol-driven clients

If a client generated with duneproject/built with dunecontrol has a
dependency to opm-core, the macros defined in this file is expected
to exist and will be called to search for the opm-core library.

All that is done here is to use the pkg-config helper module and
import the configuration that was written by the CMake system (which
even may have been called earlier in the same dunecontrol "session")

m4/opm_core.m4

@@ -0,0 +1,12 @@
+dnl -*- autoconf -*-
+
+dnl locate opm-core library itself; this macro is called by every module
+dnl that depends on opm-core.
+AC_DEFUN([OPM_CORE_CHECK_MODULE],
+[
+ OPM_CHECK_PKG_MODULE([opm-core],[1.0],[OPM Core Library])
+])
+
+dnl find all prerequisites of opm-core; nothing to do here since this
+dnl is done by the CMake module and then stored in the -config file.
+AC_DEFUN([OPM_CORE_CHECKS],[])