occi: defer symbol resolution till runtime for osx

plugins/input/occi/build.py

@@ -43,6 +43,16 @@ libraries.append(env['ICU_LIB_NAME'])
 if env['PLUGIN_LINKING'] == 'shared':
     libraries.append(env['MAPNIK_NAME'])
 
+    # libocci.dylib, at least for 11.2 links to libstdc++
+    # so we defer symbol resolution to runtime in order to
+    # dodge linking errors like
+    # Undefined symbols for architecture x86_64:
+    #   "std::string::_Rep::_M_destroy(std::allocator<char> const&)", referenced from:
+    #      RegisterClasses(oracle::occi::Environment*) in spatial_classesm.os
+
+    if env['PLATFORM'] == 'Darwin':
+        plugin_env.Append(LINKFLAGS='-undefined dynamic_lookup')
+
     TARGET = plugin_env.SharedLibrary('../%s' % PLUGIN_NAME,
                                       SHLIBPREFIX='',
                                       SHLIBSUFFIX='.input',