diff --git a/libc/bionic/fortify.cpp b/libc/bionic/fortify.cpp
index 944cfca..3bd9e68 100644
--- a/libc/bionic/fortify.cpp
+++ b/libc/bionic/fortify.cpp
@@ -80,17 +80,17 @@
 
 int __FD_ISSET_chk(int fd, const fd_set* set, size_t set_size) {
   __check_fd_set("FD_ISSET", fd, set_size);
-  return FD_ISSET(fd, set);
+  return __FD_ISSET(fd, set);
 }
 
 void __FD_CLR_chk(int fd, fd_set* set, size_t set_size) {
   __check_fd_set("FD_CLR", fd, set_size);
-  FD_CLR(fd, set);
+  __FD_CLR(fd, set);
 }
 
 void __FD_SET_chk(int fd, fd_set* set, size_t set_size) {
   __check_fd_set("FD_SET", fd, set_size);
-  FD_SET(fd, set);
+  __FD_SET(fd, set);
 }
 
 char* __fgets_chk(char* dst, int supplied_size, FILE* stream, size_t dst_len_from_compiler) {
diff --git a/libc/include/sys/cdefs.h b/libc/include/sys/cdefs.h
index 5760689..201f40a 100644
--- a/libc/include/sys/cdefs.h
+++ b/libc/include/sys/cdefs.h
@@ -289,14 +289,22 @@
 #  endif
 #endif
 
+// As we move some FORTIFY checks to be always on, __bos needs to be
+// always available.
 #if defined(__BIONIC_FORTIFY)
 #  if _FORTIFY_SOURCE == 2
 #    define __bos_level 1
 #  else
 #    define __bos_level 0
 #  endif
-#  define __bosn(s, n) __builtin_object_size((s), (n))
-#  define __bos(s) __bosn((s), __bos_level)
+#else
+#  define __bos_level 0
+#endif
+
+#define __bosn(s, n) __builtin_object_size((s), (n))
+#define __bos(s) __bosn((s), __bos_level)
+
+#if defined(__BIONIC_FORTIFY)
 #  define __bos0(s) __bosn((s), 0)
 #  if defined(__clang__)
 #    define __pass_object_size_n(n) __attribute__((pass_object_size(n)))
diff --git a/libc/include/sys/select.h b/libc/include/sys/select.h
index 603a5a6..e58df21 100644
--- a/libc/include/sys/select.h
+++ b/libc/include/sys/select.h
@@ -63,15 +63,20 @@
 void __FD_SET_chk(int, fd_set*, size_t) __INTRODUCED_IN(21);
 int __FD_ISSET_chk(int, const fd_set*, size_t) __INTRODUCED_IN(21);
 
-#if defined(__BIONIC_FORTIFY) && __ANDROID_API__ >= __ANDROID_API_L__
+#define __FD_CLR(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] &= ~__FDMASK(fd))
+#define __FD_SET(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] |= __FDMASK(fd))
+#define __FD_ISSET(fd, set) ((__FDS_BITS(const fd_set*,set)[__FDELT(fd)] & __FDMASK(fd)) != 0)
+
+
+#if __ANDROID_API__ >= __ANDROID_API_L__
 #define FD_CLR(fd, set) __FD_CLR_chk(fd, set, __bos(set))
 #define FD_SET(fd, set) __FD_SET_chk(fd, set, __bos(set))
 #define FD_ISSET(fd, set) __FD_ISSET_chk(fd, set, __bos(set))
 #else
-#define FD_CLR(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] &= ~__FDMASK(fd))
-#define FD_SET(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] |= __FDMASK(fd))
-#define FD_ISSET(fd, set) ((__FDS_BITS(const fd_set*,set)[__FDELT(fd)] & __FDMASK(fd)) != 0)
-#endif /* defined(__BIONIC_FORTIFY) && __ANDROID_API >= 21 */
+#define FD_CLR(fd, set) __FD_CLR(fd, set)
+#define FD_SET(fd, set) __FD_SET(fd, set)
+#define FD_ISSET(fd, set) __FD_ISSET(fd, set)
+#endif /* __ANDROID_API >= 21 */
 
 int select(int __fd_count, fd_set* __read_fds, fd_set* __write_fds, fd_set* __exception_fds, struct timeval* __timeout);
 int pselect(int __fd_count, fd_set* __read_fds, fd_set* __write_fds, fd_set* __exception_fds, const struct timespec* __timeout, const sigset_t* __mask);