Remove <signal.h> inlines for obsolete API levels.

The next NDK to take these headers only supports API 21 and later.

Test: treehugger
Change-Id: I8fe617e6eb781629ddf0b98b0037a9b3e54c559c
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_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/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