diff --git a/external/Touch.Unit b/external/Touch.Unit
index b4e8606a8525..dafdf9f44f8f 160000
--- a/external/Touch.Unit
+++ b/external/Touch.Unit
@@ -1 +1 @@
-Subproject commit b4e8606a85255f2456b0b20d5a0732298fa1ad36
+Subproject commit dafdf9f44f8fada4e47e2abd0c95c9e494377a8c
diff --git a/src/Makefile b/src/Makefile
index 07897ce3b2b9..b00381e63604 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -244,6 +244,7 @@ $(IOS_BUILD_DIR)/reference%MonoTouch.NUnitLite.dll $(IOS_BUILD_DIR)/reference%Mo
 	$(call Q_PROF_CSC,ios) $(IOS_CSC) -nologo -out:$(basename $@).dll -target:library -debug:portable -optimize -publicsign \
 		-deterministic \
 		-keyfile:$(PRODUCT_KEY_PATH) -r:$(IOS_BUILD_DIR)/reference/Xamarin.iOS.dll -define:MONO -r:$(IOS_BUILD_DIR)/reference/MonoTouch.Dialog-1.dll -r:$(MONOTOUCH_MONO_PATH)/System.dll -r:$(MONOTOUCH_MONO_PATH)/System.Xml.dll \
+		-r:$(MONOTOUCH_MONO_PATH)/System.Core.dll \
 		-nowarn:3006,612,649,414,1635,659 \
 		-define:NUNITLITE,CLR_4_0,NET_4_5,__MOBILE__,MONO $(IOS_DEFINES) \
 		-define:XAMCORE_2_0,__UNIFIED__ \
@@ -838,6 +839,7 @@ $(WATCH_BUILD_DIR)/reference/Xamarin.WatchOS.pdb: $(WATCH_BUILD_DIR)/watch-32/Xa
 $(WATCH_BUILD_DIR)/reference/MonoTouch.NUnitLite%dll $(WATCH_BUILD_DIR)/reference/MonoTouch.NUnitLite%pdb: $(WATCHOS_TOUCHUNIT_SOURCES) $(PRODUCT_KEY_PATH) $(WATCH_BUILD_DIR)/reference/Xamarin.WatchOS.dll
 	$(call Q_PROF_CSC,watch) $(SYSTEM_CSC) -features:strict -nologo -out:$(basename $@).dll -target:library -debug:portable -optimize -publicsign -noconfig -nostdlib \
 		-keyfile:$(PRODUCT_KEY_PATH) -r:$(WATCH_BUILD_DIR)/reference/Xamarin.WatchOS.dll -r:$(MONOTOUCH_WATCH_MONO_PATH)/mscorlib.dll -r:$(MONOTOUCH_WATCH_MONO_PATH)/System.dll -r:$(MONOTOUCH_WATCH_MONO_PATH)/System.Xml.dll \
+		-r:$(MONOTOUCH_WATCH_MONO_PATH)/System.Core.dll \
 		-nowarn:3006,612,649,414,1635,659 \
 		-define:NUNITLITE,CLR_4_0,NET_4_5,__MOBILE__,MONO $(WATCH_DEFINES) \
 		-define:XAMCORE_2_0,__UNIFIED__ \
@@ -1069,6 +1071,7 @@ $(TVOS_BUILD_DIR)/reference/Xamarin.TVOS.pdb: $(TVOS_BUILD_DIR)/tvos-64/Xamarin.
 $(TVOS_BUILD_DIR)/reference/MonoTouch.NUnitLite%dll $(TVOS_BUILD_DIR)/reference/MonoTouch.NUnitLite%pdb: $(TVOS_TOUCHUNIT_SOURCES) $(PRODUCT_KEY_PATH) $(TVOS_BUILD_DIR)/reference/Xamarin.TVOS.dll $(TVOS_BUILD_DIR)/reference/MonoTouch.Dialog-1.dll
 	$(call Q_PROF_CSC,tvos) $(SYSTEM_CSC) -features:strict -nologo -r:$(MONOTOUCH_TV_MONO_PATH)/mscorlib.dll -out:$(basename $@).dll -target:library -debug:portable -optimize -noconfig -nostdlib -publicsign \
 		-keyfile:$(PRODUCT_KEY_PATH) -r:$(TVOS_BUILD_DIR)/reference/Xamarin.TVOS.dll -r:$(TVOS_BUILD_DIR)/reference/MonoTouch.Dialog-1.dll -r:$(MONOTOUCH_TV_MONO_PATH)/System.dll -r:$(MONOTOUCH_TV_MONO_PATH)/System.Xml.dll \
+		-r:$(MONOTOUCH_TV_MONO_PATH)/System.Core.dll \
 		-nowarn:3006,612,649,414,1635,659 \
 		-define:NUNITLITE,CLR_4_0,NET_4_5,__MOBILE__,MONO $(TVOS_DEFINES) \
 		-define:XAMCORE_2_0,__UNIFIED__ \