diff -ruw source/include/curl/curl.h source-new/include/curl/curl.h
--- source/include/curl/curl.h	2018-10-30 10:53:59.000000000 -0600
+++ source-new/include/curl/curl.h	2018-12-10 12:42:52.504393368 -0700
@@ -74,7 +74,7 @@
 #if defined(_AIX) || defined(__NOVELL_LIBC__) || defined(__NetBSD__) || \
     defined(__minix) || defined(__SYMBIAN32__) || defined(__INTEGRITY) || \
     defined(ANDROID) || defined(__ANDROID__) || defined(__OpenBSD__) || \
-    defined(__CYGWIN__) || \
+    defined(__CYGWIN__) || defined(__redox__) || \
    (defined(__FreeBSD_version) && (__FreeBSD_version < 800000))
 #include <sys/select.h>
 #endif