diff --git a/libc/bionic/__libc_current_sigrtmax.cpp b/libc/bionic/__libc_current_sigrtmax.cpp
index 32179bb..328ede1 100644
--- a/libc/bionic/__libc_current_sigrtmax.cpp
+++ b/libc/bionic/__libc_current_sigrtmax.cpp
@@ -28,8 +28,6 @@
 
 #include <signal.h>
 
-int __libc_current_sigrtmax(void) {
-  // If you change this, also change __ndk_legacy___libc_current_sigrtmax
-  // in <android/legacy_signal_inlines.h> to match.
+int __libc_current_sigrtmax() {
   return __SIGRTMAX;
 }
diff --git a/libc/include/android/legacy_errno_inlines.h b/libc/include/android/legacy_errno_inlines.h
deleted file mode 100644
index fcbca13..0000000
--- a/libc/include/android/legacy_errno_inlines.h
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#pragma once
-
-#include <sys/cdefs.h>
-
-#if __ANDROID_API__ < 21
-
-#include <errno.h>
-
-__BEGIN_DECLS
-
-static __inline int __attribute__((deprecated)) __set_errno(int n) {
-  errno = n;
-  return -1;
-}
-
-__END_DECLS
-
-#endif
diff --git a/libc/include/android/legacy_signal_inlines.h b/libc/include/android/legacy_signal_inlines.h
deleted file mode 100644
index f2bdcf6..0000000
--- a/libc/include/android/legacy_signal_inlines.h
+++ /dev/null
@@ -1,143 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#pragma once
-
-#include <sys/cdefs.h>
-
-#if __ANDROID_API__ < 21
-
-#include <errno.h>
-#include <signal.h>
-#include <string.h>
-
-__BEGIN_DECLS
-
-sighandler_t bsd_signal(int __signal, sighandler_t __handler) __REMOVED_IN(21);
-
-/* These weren't introduced until L. */
-int __libc_current_sigrtmax() __attribute__((__weak__)) __VERSIONER_NO_GUARD;
-int __libc_current_sigrtmin() __attribute__((__weak__)) __VERSIONER_NO_GUARD;
-
-static __inline int __ndk_legacy___libc_current_sigrtmax() {
-  /*
-   * The NDK doesn't use libclang_rt.builtins yet (https://github.com/android/ndk/issues/1231) so it
-   * can't use __builtin_available, but the platform builds with -Werror=unguarded-availability so
-   * it requires __builtin_available.
-   */
-#if defined(__ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__)
-  if (__builtin_available(android 21, *)) {
-#else
-  if (__libc_current_sigrtmax) {
-#endif
-    return __libc_current_sigrtmax();
-  }
-  return __SIGRTMAX; /* Should match __libc_current_sigrtmax. */
-}
-
-static __inline int __ndk_legacy___libc_current_sigrtmin() {
-  /*
-   * The NDK doesn't use libclang_rt.builtins yet (https://github.com/android/ndk/issues/1231) so it
-   * can't use __builtin_available, but the platform builds with -Werror=unguarded-availability so
-   * it requires __builtin_available.
-   */
-#if defined(__ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__)
-  if (__builtin_available(android 21, *)) {
-#else
-  if (__libc_current_sigrtmin) {
-#endif
-    return __libc_current_sigrtmin();
-  }
-  return __SIGRTMIN + 7; /* Should match __libc_current_sigrtmin. */
-}
-
-#undef SIGRTMAX
-#define SIGRTMAX __ndk_legacy___libc_current_sigrtmax()
-#undef SIGRTMIN
-#define SIGRTMIN __ndk_legacy___libc_current_sigrtmin()
-
-static __inline int sigismember(const sigset_t *set, int signum) {
-  /* Signal numbers start at 1, but bit positions start at 0. */
-  int bit = signum - 1;
-  const unsigned long *local_set = (const unsigned long *)set;
-  if (set == NULL || bit < 0 || bit >= (int)(8 * sizeof(sigset_t))) {
-    errno = EINVAL;
-    return -1;
-  }
-  return (int)((local_set[bit / (8 * sizeof(long))] >> (bit % (8 * sizeof(long)))) & 1);
-}
-
-static __inline int sigaddset(sigset_t *set, int signum) {
-  /* Signal numbers start at 1, but bit positions start at 0. */
-  int bit = signum - 1;
-  unsigned long *local_set = (unsigned long *)set;
-  if (set == NULL || bit < 0 || bit >= (int)(8 * sizeof(sigset_t))) {
-    errno = EINVAL;
-    return -1;
-  }
-  local_set[bit / (8 * sizeof(long))] |= 1UL << (bit % (8 * sizeof(long)));
-  return 0;
-}
-
-static __inline int sigdelset(sigset_t *set, int signum) {
-  /* Signal numbers start at 1, but bit positions start at 0. */
-  int bit = signum - 1;
-  unsigned long *local_set = (unsigned long *)set;
-  if (set == NULL || bit < 0 || bit >= (int)(8 * sizeof(sigset_t))) {
-    errno = EINVAL;
-    return -1;
-  }
-  local_set[bit / (8 * sizeof(long))] &= ~(1UL << (bit % (8 * sizeof(long))));
-  return 0;
-}
-
-static __inline int sigemptyset(sigset_t *set) {
-  if (set == NULL) {
-    errno = EINVAL;
-    return -1;
-  }
-  memset(set, 0, sizeof(sigset_t));
-  return 0;
-}
-
-static __inline int sigfillset(sigset_t *set) {
-  if (set == NULL) {
-    errno = EINVAL;
-    return -1;
-  }
-  memset(set, ~0, sizeof(sigset_t));
-  return 0;
-}
-
-static __inline sighandler_t signal(int s, sighandler_t f) {
-  return bsd_signal(s, f);
-}
-
-__END_DECLS
-
-#endif
diff --git a/libc/include/android/legacy_sys_mman_inlines.h b/libc/include/android/legacy_sys_mman_inlines.h
deleted file mode 100644
index 04b3e97..0000000
--- a/libc/include/android/legacy_sys_mman_inlines.h
+++ /dev/null
@@ -1,71 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#pragma once
-
-#include <sys/cdefs.h>
-
-#if __ANDROID_API__ < 21
-
-#include <errno.h>
-#include <sys/mman.h>
-#include <unistd.h>
-
-__BEGIN_DECLS
-
-/*
- * While this was never an inline, this function alone has caused most of the
- * bug reports related to _FILE_OFFSET_BITS=64. Providing an inline for it
- * should allow a lot more code to build with _FILE_OFFSET_BITS=64 when
- * targeting pre-L.
- */
-static __inline void* mmap64(void* __addr, size_t __size, int __prot, int __flags, int __fd,
-                             off64_t __offset) __RENAME(mmap64);
-static __inline void* mmap64(void* __addr, size_t __size, int __prot, int __flags, int __fd,
-                             off64_t __offset) {
-  const int __mmap2_shift = 12; // 2**12 == 4096
-  if (__offset < 0 || (__offset & ((1UL << __mmap2_shift) - 1)) != 0) {
-    errno = EINVAL;
-    return MAP_FAILED;
-  }
-
-  // prevent allocations large enough for `end - start` to overflow
-  size_t __rounded = __BIONIC_ALIGN(__size, PAGE_SIZE);
-  if (__rounded < __size || __rounded > PTRDIFF_MAX) {
-    errno = ENOMEM;
-    return MAP_FAILED;
-  }
-
-  extern void* __mmap2(void* __addr, size_t __size, int __prot, int __flags, int __fd,
-                       size_t __offset);
-  return __mmap2(__addr, __size, __prot, __flags, __fd, __offset >> __mmap2_shift);
-}
-
-__END_DECLS
-
-#endif
diff --git a/libc/include/bits/threads_inlines.h b/libc/include/bits/threads_inlines.h
index afaed64..17de4a1 100644
--- a/libc/include/bits/threads_inlines.h
+++ b/libc/include/bits/threads_inlines.h
@@ -103,12 +103,10 @@
   return __bionic_thrd_error(pthread_mutex_lock(__mtx));
 }
 
-#if __ANDROID_API__ >= 21
 __BIONIC_THREADS_INLINE int mtx_timedlock(mtx_t* __mtx,
                                           const struct timespec* __timeout) {
   return __bionic_thrd_error(pthread_mutex_timedlock(__mtx, __timeout));
 }
-#endif
 
 __BIONIC_THREADS_INLINE int mtx_trylock(mtx_t* __mtx) {
   return __bionic_thrd_error(pthread_mutex_trylock(__mtx));
diff --git a/libc/include/errno.h b/libc/include/errno.h
index b6a4c7e..ab56bb3 100644
--- a/libc/include/errno.h
+++ b/libc/include/errno.h
@@ -58,5 +58,3 @@
 #define errno (*__errno())
 
 __END_DECLS
-
-#include <android/legacy_errno_inlines.h>
diff --git a/libc/include/signal.h b/libc/include/signal.h
index edfcb5d..b9aeaab 100644
--- a/libc/include/signal.h
+++ b/libc/include/signal.h
@@ -64,7 +64,6 @@
 
 int siginterrupt(int __signal, int __flag);
 
-#if __ANDROID_API__ >= 21
 sighandler_t _Nonnull signal(int __signal, sighandler_t _Nullable __handler) __INTRODUCED_IN(21);
 int sigaddset(sigset_t* _Nonnull __set, int __signal) __INTRODUCED_IN(21);
 int sigaddset64(sigset64_t* _Nonnull __set, int __signal) __INTRODUCED_IN(28);
@@ -76,9 +75,6 @@
 int sigfillset64(sigset64_t* _Nonnull __set) __INTRODUCED_IN(28);
 int sigismember(const sigset_t* _Nonnull __set, int __signal) __INTRODUCED_IN(21);
 int sigismember64(const sigset64_t* _Nonnull __set, int __signal) __INTRODUCED_IN(28);
-#else
-// Implemented as static inlines before 21.
-#endif
 
 int sigpending(sigset_t* _Nonnull __set);
 int sigpending64(sigset64_t* _Nonnull __set) __INTRODUCED_IN(28);
@@ -128,6 +124,4 @@
 
 __END_DECLS
 
-#include <android/legacy_signal_inlines.h>
-
 #endif
diff --git a/libc/include/sys/mman.h b/libc/include/sys/mman.h
index fea9332..bcf856d 100644
--- a/libc/include/sys/mman.h
+++ b/libc/include/sys/mman.h
@@ -55,17 +55,14 @@
 void* mmap(void* __addr, size_t __size, int __prot, int __flags, int __fd, off_t __offset);
 #endif
 
-#if __ANDROID_API__ >= 21
 /**
  * mmap64() is a variant of mmap() that takes a 64-bit offset even on LP32.
  *
  * See https://android.googlesource.com/platform/bionic/+/master/docs/32-bit-abi.md
  *
- * mmap64 wasn't really around until L, but we added an inline for it since it
- * allows a lot more code to compile with _FILE_OFFSET_BITS=64.
+ * Available since API level 21.
  */
 void* mmap64(void* __addr, size_t __size, int __prot, int __flags, int __fd, off64_t __offset) __INTRODUCED_IN(21);
-#endif
 
 /**
  * [munmap(2)](http://man7.org/linux/man-pages/man2/munmap.2.html)
@@ -232,5 +229,3 @@
 int posix_madvise(void* __addr, size_t __size, int __advice) __INTRODUCED_IN(23);
 
 __END_DECLS
-
-#include <android/legacy_sys_mman_inlines.h>