Add library search directories to linker options

Some older packages, and notably those that are detected by PkgConfig,
only give library names and then a list of library search directories.

Add to link_directories here in order to support this configuration,
even though it is deprecated in newer versions of CMake.

CMakeLists.txt

@@ -99,6 +99,7 @@ remove_duplicate_libraries (opm-core)
 
 # create this library
 include_directories (${opm-core_INCLUDE_DIRS})
+link_directories (${opm-core_LIBRARY_DIRS})
 add_definitions (${opm-core_DEFINITIONS})
 add_library (opmcore SHARED ${opm-core_SOURCES})
 set_target_properties (opmcore PROPERTIES

cmake/Modules/UseOpmFind.cmake

@@ -29,6 +29,7 @@ set (_opm_proj_vars
   LIBRARIES
   DEFINITIONS
   INCLUDE_DIRS
+  LIBRARY_DIRS
   CONFIG_VARS
   )