diff --git a/basis/alien/libraries/unix/platforms.txt b/basis/alien/libraries/unix/platforms.txt
new file mode 100644
index 0000000000..509143d863
--- /dev/null
+++ b/basis/alien/libraries/unix/platforms.txt
@@ -0,0 +1 @@
+unix
diff --git a/basis/alien/libraries/windows/platforms.txt b/basis/alien/libraries/windows/platforms.txt
new file mode 100644
index 0000000000..8e1a55995e
--- /dev/null
+++ b/basis/alien/libraries/windows/platforms.txt
@@ -0,0 +1 @@
+windows