[scr] find MGIS package

scripts/cmake/Find.cmake

@@ -172,3 +172,7 @@ find_package(CVODE)
 if(CVODE_FOUND)
     add_definitions(-DCVODE_FOUND)
 endif() # CVODE_FOUND
+
+if(OGS_USE_MFRONT)
+    find_package(MGIS REQUIRED)
+endif()

scripts/cmake/FindMGIS.cmake

+# Find the MGIS includes and libraries
+#
+#    MGIS_INCLUDE_DIR - Where to find MGIS headers
+#    MGIS_LIBRARY     - The MGIS library to link against.
+#    MGIS_FOUND       - Do not attempt to use if "no" or undefined.
+#
+# MGIS, the MFront Generic Interface Support library
+# See https://github.com/thelfer/MFrontGenericInterfaceSupport
+#     http://tfel.sourceforge.net/generic-behaviours-interface.html
+
+find_path(MGIS_INCLUDE_DIR MGIS)
+
+find_library(MGIS_LIBRARY MFrontGenericInterface)
+
+include(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(MGIS DEFAULT_MSG MGIS_LIBRARY MGIS_INCLUDE_DIR)