LIB_MCS_FLAGS = -nowarn:618 -d:CONFIGURATION_2_0 $(REFERENCE_SOURCES_FLAGS) -unsafe $(RESOURCE_FILES:%=-resource:%)
+ifdef DYNAMIC_BTLS
+LIB_MCS_FLAGS += -d:DYNAMIC_BTLS
+endif
+
ifndef NO_THREAD_ABORT
REFERENCE_SOURCES_FLAGS += -d:MONO_FEATURE_THREAD_ABORT
TEST_MCS_FLAGS += -d:MONO_FEATURE_THREAD_ABORT