diff --git a/libc/include/bits/fortify/fcntl.h b/libc/include/bits/fortify/fcntl.h
index 7fe60f4..1f6ebad 100644
--- a/libc/include/bits/fortify/fcntl.h
+++ b/libc/include/bits/fortify/fcntl.h
@@ -59,7 +59,7 @@
 int open(const char* const __pass_object_size pathname, int flags)
         __overloadable
         __clang_error_if(__open_modes_useful(flags), "'open' " __open_too_few_args_error) {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __open_2(pathname, flags);
 #else
     return __open_real(pathname, flags);
@@ -83,7 +83,7 @@
 int openat(int dirfd, const char* const __pass_object_size pathname, int flags)
         __overloadable
         __clang_error_if(__open_modes_useful(flags), "'openat' " __open_too_few_args_error) {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __openat_2(dirfd, pathname, flags);
 #else
     return __openat_real(dirfd, pathname, flags);
@@ -98,7 +98,6 @@
     return __openat_real(dirfd, pathname, flags, modes);
 }
 
-#if __ANDROID_API__ >= 21
 /* Note that open == open64, so we reuse those bits in the open64 variants below.  */
 
 __BIONIC_ERROR_FUNCTION_VISIBILITY
@@ -139,7 +138,6 @@
                            "'openat64' " __open_useless_modes_warning) {
     return openat(dirfd, pathname, flags, modes);
 }
-#endif /* __ANDROID_API__ >= 21 */
 
 #undef __open_too_many_args_error
 #undef __open_too_few_args_error
diff --git a/libc/include/bits/fortify/poll.h b/libc/include/bits/fortify/poll.h
index 143153c..0b5cd4b 100644
--- a/libc/include/bits/fortify/poll.h
+++ b/libc/include/bits/fortify/poll.h
@@ -54,7 +54,6 @@
   return __call_bypassing_fortify(poll)(fds, fd_count, timeout);
 }
 
-#if __ANDROID_API__ >= 21
 __BIONIC_FORTIFY_INLINE
 int ppoll(struct pollfd* const fds __pass_object_size, nfds_t fd_count, const struct timespec* timeout, const sigset_t* mask)
     __overloadable
@@ -69,7 +68,6 @@
 #endif
   return __call_bypassing_fortify(ppoll)(fds, fd_count, timeout, mask);
 }
-#endif /* __ANDROID_API__ >= 21 */
 
 #if __ANDROID_API__ >= 28
 __BIONIC_FORTIFY_INLINE
diff --git a/libc/include/bits/fortify/stat.h b/libc/include/bits/fortify/stat.h
index 2d42a51..9b4ade2 100644
--- a/libc/include/bits/fortify/stat.h
+++ b/libc/include/bits/fortify/stat.h
@@ -39,7 +39,7 @@
     __overloadable
     __enable_if(1, "")
     __clang_error_if(mode & ~0777, "'umask' called with invalid mode") {
-#if __ANDROID_API__ >= 18 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
   return __umask_chk(mode);
 #else
   return __umask_real(mode);
diff --git a/libc/include/bits/fortify/stdio.h b/libc/include/bits/fortify/stdio.h
index 77bdbb4..95db017 100644
--- a/libc/include/bits/fortify/stdio.h
+++ b/libc/include/bits/fortify/stdio.h
@@ -36,7 +36,7 @@
 
 #if defined(__BIONIC_FORTIFY) && !defined(__BIONIC_NO_STDIO_FORTIFY)
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 /* No diag -- clang diagnoses misuses of this on its own.  */
 __BIONIC_FORTIFY_INLINE __printflike(3, 0)
 int vsnprintf(char* const __pass_object_size dest, size_t size, const char* format, va_list ap)
@@ -58,7 +58,7 @@
                 "format string will always overflow destination buffer")
     __errorattr("format string will always overflow destination buffer");
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 __BIONIC_FORTIFY_VARIADIC __printflike(2, 3)
 int sprintf(char* const __pass_object_size dest, const char* format, ...) __overloadable {
     va_list va;
@@ -126,7 +126,7 @@
         __clang_error_if(size < 0, "in call to 'fgets', size should not be negative")
         __clang_error_if(__bos_unevaluated_lt(__bos(dest), size),
                          "in call to 'fgets', size is larger than the destination buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos(dest);
 
     if (!__bos_dynamic_check_impl_and(bos, >=, (size_t)size, size >= 0)) {
diff --git a/libc/include/bits/fortify/string.h b/libc/include/bits/fortify/string.h
index 08bce2d..f668b9f 100644
--- a/libc/include/bits/fortify/string.h
+++ b/libc/include/bits/fortify/string.h
@@ -40,7 +40,7 @@
 #if defined(__BIONIC_FORTIFY)
 extern void* __memrchr_real(const void*, int, size_t) __RENAME(memrchr);
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 /* No diag -- clang diagnoses misuses of this on its own.  */
 __BIONIC_FORTIFY_INLINE
 void* memcpy(void* const dst __pass_object_size0, const void* src, size_t copy_amount)
@@ -82,7 +82,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_le(__bos(dst), __builtin_strlen(src)),
                          "'stpcpy' called with string bigger than buffer") {
-#if __ANDROID_API__ >= 21 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __builtin___stpcpy_chk(dst, src, __bos(dst));
 #else
     return __builtin_stpcpy(dst, src);
@@ -95,7 +95,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_le(__bos(dst), __builtin_strlen(src)),
                          "'strcpy' called with string bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __builtin___strcpy_chk(dst, src, __bos(dst));
 #else
     return __builtin_strcpy(dst, src);
@@ -107,14 +107,14 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_le(__bos(dst), __builtin_strlen(src)),
                          "'strcat' called with string bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __builtin___strcat_chk(dst, src, __bos(dst));
 #else
     return __builtin_strcat(dst, src);
 #endif
 }
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 /* No diag -- clang diagnoses misuses of this on its own.  */
 __BIONIC_FORTIFY_INLINE
 char* strncat(char* const dst __pass_object_size, const char* src, size_t n)
@@ -130,7 +130,7 @@
         __diagnose_as_builtin(__builtin_memset, 1, 2, 3)
         /* If you're a user who wants this warning to go away: use `(&memset)(foo, bar, baz)`. */
         __clang_warning_if(c && !n, "'memset' will set 0 bytes; maybe the arguments got flipped?") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __builtin___memset_chk(s, c, n, __bos0(s));
 #else
     return __builtin_memset(s, c, n);
@@ -161,7 +161,7 @@
 }
 #endif
 
-#if __ANDROID_API__ >= 21 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 /* No diag -- clang diagnoses misuses of this on its own.  */
 __BIONIC_FORTIFY_INLINE
 char* stpncpy(char* const dst __pass_object_size, const char* const src __pass_object_size, size_t n)
@@ -200,7 +200,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_lt(__bos(dst), size),
                          "'strlcpy' called with size bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __strlcpy_chk(dst, src, size, __bos(dst));
 #else
     return __call_bypassing_fortify(strlcpy)(dst, src, size);
@@ -212,14 +212,14 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_lt(__bos(dst), size),
                          "'strlcat' called with size bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __strlcat_chk(dst, src, size, __bos(dst));
 #else
     return __call_bypassing_fortify(strlcat)(dst, src, size);
 #endif
 }
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 __BIONIC_FORTIFY_INLINE
 size_t strlen(const char* const s __pass_object_size0) __overloadable {
     return __strlen_chk(s, __bos0(s));
@@ -228,7 +228,7 @@
 
 __BIONIC_FORTIFY_INLINE
 char* strchr(const char* const s __pass_object_size, int c) __overloadable {
-#if  __ANDROID_API__ >= 18 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos(s);
 
     if (bos != __BIONIC_FORTIFY_UNKNOWN_SIZE) {
@@ -240,7 +240,7 @@
 
 __BIONIC_FORTIFY_INLINE
 char* strrchr(const char* const s __pass_object_size, int c) __overloadable {
-#if  __ANDROID_API__ >= 18 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos(s);
 
     if (bos != __BIONIC_FORTIFY_UNKNOWN_SIZE) {
diff --git a/libc/include/bits/fortify/strings.h b/libc/include/bits/fortify/strings.h
index 65fc5f1..5515ef9 100644
--- a/libc/include/bits/fortify/strings.h
+++ b/libc/include/bits/fortify/strings.h
@@ -33,7 +33,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_lt(__bos0(dst), len),
                          "'bcopy' called with size bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos0(dst);
     if (!__bos_trivially_ge(bos, len)) {
         __builtin___memmove_chk(dst, src, len, bos);
@@ -48,7 +48,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_lt(__bos0(b), len),
                          "'bzero' called with size bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos0(b);
     if (!__bos_trivially_ge(bos, len)) {
         __builtin___memset_chk(b, 0, len, bos);
diff --git a/libc/include/bits/fortify/unistd.h b/libc/include/bits/fortify/unistd.h
index 49a3946..335d0b5 100644
--- a/libc/include/bits/fortify/unistd.h
+++ b/libc/include/bits/fortify/unistd.h
@@ -152,7 +152,7 @@
         __overloadable
         __error_if_overflows_ssizet(count, read)
         __error_if_overflows_objectsize(count, __bos0(buf), read) {
-#if __ANDROID_API__ >= 21 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos0(buf);
 
     if (!__bos_trivially_ge_no_overflow(bos, count)) {
@@ -192,7 +192,6 @@
     return __call_bypassing_fortify(readlink)(path, buf, size);
 }
 
-#if __ANDROID_API__ >= 21
 __BIONIC_FORTIFY_INLINE
 ssize_t readlinkat(int dirfd, const char* path, char* const __pass_object_size buf, size_t size)
         __overloadable
@@ -207,7 +206,6 @@
 #endif
     return __call_bypassing_fortify(readlinkat)(dirfd, path, buf, size);
 }
-#endif /* __ANDROID_API__ >= 21 */
 
 #undef __bos_trivially_ge_no_overflow
 #undef __enable_if_no_overflow_ssizet
diff --git a/libc/include/fcntl.h b/libc/include/fcntl.h
index 1ec932b..a8db387 100644
--- a/libc/include/fcntl.h
+++ b/libc/include/fcntl.h
@@ -84,7 +84,6 @@
 /** Flag for open(). */
 #define O_RSYNC O_SYNC
 
-#if __ANDROID_API__ >= 21
 /** Flag for splice(). */
 #define SPLICE_F_MOVE 1
 /** Flag for splice(). */
@@ -93,7 +92,6 @@
 #define SPLICE_F_MORE 4
 /** Flag for splice(). */
 #define SPLICE_F_GIFT 8
-#endif
 
 #if __ANDROID_API__ >= 26
 /** Flag for sync_file_range(). */
diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index 22f949b..130a72f 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -58,9 +58,7 @@
 #define PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP { { ((PTHREAD_MUTEX_ERRORCHECK & 3) << 14) } }
 
 #define PTHREAD_COND_INITIALIZER  { { 0 } }
-#if __ANDROID_API__ >= 21
 #define PTHREAD_COND_INITIALIZER_MONOTONIC_NP  { { 1 << 1 } }
-#endif
 
 #define PTHREAD_RWLOCK_INITIALIZER  { { 0 } }
 
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 9de12a4..f4b2911 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -136,20 +136,8 @@
 int vfprintf(FILE* __fp, const char* __fmt, va_list __args) __printflike(2, 0);
 int vprintf(const char* __fp, va_list __args) __printflike(1, 0);
 
-#if __ANDROID_API__ >= 21
 int dprintf(int __fd, const char* __fmt, ...) __printflike(2, 3) __INTRODUCED_IN(21);
 int vdprintf(int __fd, const char* __fmt, va_list __args) __printflike(2, 0) __INTRODUCED_IN(21);
-#else
-/*
- * Old versions of Android called these fdprintf and vfdprintf out of fears that the glibc names
- * would collide with user debug printfs.
- *
- * Allow users to just use dprintf and vfdprintf on any version by renaming those calls to their
- * legacy equivalents if needed.
- */
-int dprintf(int __fd, const char* __fmt, ...) __RENAME(fdprintf) __printflike(2, 3);
-int vdprintf(int __fd, const char* __fmt, va_list __args) __RENAME(vfdprintf) __printflike(2, 0);
-#endif
 
 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ < 201112L) || \
     (defined(__cplusplus) && __cplusplus <= 201103L)
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 2ff8089..c185ec7 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -43,11 +43,7 @@
 
 __noreturn void abort(void) __attribute__((__nomerge__));
 __noreturn void exit(int __status);
-#if __ANDROID_API__ >= 21
 __noreturn void _Exit(int __status) __INTRODUCED_IN(21);
-#else
-__noreturn void _Exit(int) __RENAME(_exit);
-#endif
 
 int atexit(void (* _Nonnull __fn)(void));
 
diff --git a/libc/include/sys/epoll.h b/libc/include/sys/epoll.h
index 302c8c3..9e09408 100644
--- a/libc/include/sys/epoll.h
+++ b/libc/include/sys/epoll.h
@@ -40,21 +40,6 @@
 int epoll_create(int __size);
 int epoll_create1(int __flags) __INTRODUCED_IN(21);
 
-/*
- * Some third-party code uses the existence of EPOLL_CLOEXEC to detect the
- * availability of epoll_create1. This is not correct, since having up-to-date
- * UAPI headers says nothing about the C library, but for the time being we
- * don't want to harm adoption to the unified headers. We'll undef EPOLL_CLOEXEC
- * if we don't have epoll_create1 for the time being, and maybe revisit this
- * later.
- *
- * https://github.com/android-ndk/ndk/issues/302
- * https://github.com/android-ndk/ndk/issues/394
- */
-#if __ANDROID_API__ < 21 && defined(EPOLL_CLOEXEC)
-#undef EPOLL_CLOEXEC
-#endif
-
 int epoll_ctl(int __epoll_fd, int __op, int __fd, struct epoll_event* __BIONIC_COMPLICATED_NULLNESS __event);
 int epoll_wait(int __epoll_fd, struct epoll_event* _Nonnull __events, int __event_count, int __timeout_ms);
 int epoll_pwait(int __epoll_fd, struct epoll_event* _Nonnull __events, int __event_count, int __timeout_ms, const sigset_t* _Nullable __mask) __INTRODUCED_IN(21);
diff --git a/libc/include/sys/inotify.h b/libc/include/sys/inotify.h
index 37fbf99..c3cdc85 100644
--- a/libc/include/sys/inotify.h
+++ b/libc/include/sys/inotify.h
@@ -37,21 +37,8 @@
 
 __BEGIN_DECLS
 
-/*
- * Some third-party code uses the existence of IN_CLOEXEC/IN_NONBLOCK to detect
- * the availability of inotify_init1. This is not correct, since
- * `syscall(__NR_inotify_init1, IN_CLOEXEC)` is still valid even if the C
- * library doesn't have that function, but for the time being we don't want to
- * harm adoption to the unified headers. We'll avoid defining IN_CLOEXEC and
- * IN_NONBLOCK if we don't have inotify_init1 for the time being, and maybe
- * revisit this later.
- *
- * https://github.com/android-ndk/ndk/issues/394
- */
-#if __ANDROID_API__ >= 21
 #define IN_CLOEXEC O_CLOEXEC
 #define IN_NONBLOCK O_NONBLOCK
-#endif
 
 int inotify_init(void);
 int inotify_init1(int __flags) __INTRODUCED_IN(21);
diff --git a/libc/include/sys/select.h b/libc/include/sys/select.h
index 65571eb..06914a6 100644
--- a/libc/include/sys/select.h
+++ b/libc/include/sys/select.h
@@ -79,8 +79,6 @@
 #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__ >= 21
-
 /** Removes `fd` from the given set. Use <poll.h> instead. */
 #define FD_CLR(fd, set) __FD_CLR_chk(fd, set, __bos(set))
 /** Adds `fd` to the given set. Use <poll.h> instead. */
@@ -88,17 +86,6 @@
 /** Tests whether `fd` is in the given set. Use <poll.h> instead. */
 #define FD_ISSET(fd, set) __FD_ISSET_chk(fd, set, __bos(set))
 
-#else
-
-/** Removes `fd` from the given set. Use <poll.h> instead. */
-#define FD_CLR(fd, set) __FD_CLR(fd, set)
-/** Adds `fd` to the given set. Use <poll.h> instead. */
-#define FD_SET(fd, set) __FD_SET(fd, set)
-/** Tests whether `fd` is in the given set. Use <poll.h> instead. */
-#define FD_ISSET(fd, set) __FD_ISSET(fd, set)
-
-#endif /* __ANDROID_API >= 21 */
-
 /**
  * [select(2)](http://man7.org/linux/man-pages/man2/select.2.html) waits on a
  * set of file descriptors.
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index 566caaa..7ad94e1 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -303,13 +303,7 @@
 
 int acct(const char* _Nullable __path);
 
-#if __ANDROID_API__ >= 21
 int getpagesize(void) __INTRODUCED_IN(21);
-#else
-static __inline__ int getpagesize(void) {
-  return sysconf(_SC_PAGESIZE);
-}
-#endif
 
 long syscall(long __number, ...);