Skip the "rebuild" part of the "ln" test on Windows

By default MSYS2 will copy and not link, altering Erlang.mk's
behavior. To properly link an option must be enabled and
administrative privileges granted.

test/core_deps.mk

@@ -194,6 +194,10 @@ core-deps-dep-built-ln: init
 	$i "Build the application"
 	$t $(MAKE) -C $(APP) $v
 
+# On MSYS2 "ln" will by default not create symbolic links because
+# it requires an option to be enabled and administrative privileges.
+# The "rebuild" part of the test is therefore skipped on Windows.
+ifneq ($(PLATFORM),msys2)
 	$i "Touch one cowlib file to mark it for recompilation"
 	$t $(SLEEP)
 	$t touch $(APP)/deps/cowlib/src/cow_http.erl
@@ -203,11 +207,13 @@ core-deps-dep-built-ln: init
 		$(APP)/cowlib/cowlib.d \
 		$(APP)/cowlib/ebin/cowlib.app \
 		$(APP)/cowlib/ebin/cow_http.beam | sort > $(APP)/EXPECT
+
 	$t $(SLEEP)
 	$t $(MAKE) -C $(APP) $v
 # Files in .git might end up modified due to the id generation in the .app file.
 	$t find $(APP)/cowlib -type f -newer $(APP)/EXPECT | grep -v ".git" | sort | diff $(APP)/EXPECT -
 	$t rm $(APP)/EXPECT
+endif
 
 core-deps-dep-commit: init