Compile time probe to fish O_NOFOLLOW out of linux headers when fcntl doesn't conform to posix-2008.
diff --git a/lib/portability.h b/lib/portability.h
index feaf789..745f8cd 100644
--- a/lib/portability.h
+++ b/lib/portability.h
@@ -145,3 +145,5 @@
 ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
 ssize_t getline(char **lineptr, size_t *n, FILE *stream);
 #endif
+
+#include "generated/portability.h"