id.c #ifdefectomy. (ifdefs belong in headers, not in C code.)
diff --git a/lib/portability.h b/lib/portability.h
index 67ac5b5..4097def 100644
--- a/lib/portability.h
+++ b/lib/portability.h
@@ -239,4 +239,7 @@
 
 #if CFG_TOYBOX_SELINUX
 #include <selinux/selinux.h>
+#else
+#define is_selinux_enabled() 0
+int getcon(void* con);
 #endif