diff --git a/libc/bionic/ffs.cpp b/libc/bionic/ffs.cpp
index b2270e5..aa7e504 100644
--- a/libc/bionic/ffs.cpp
+++ b/libc/bionic/ffs.cpp
@@ -26,8 +26,5 @@
  * SUCH DAMAGE.
  */
 
+#define __BIONIC_STRINGS_INLINE /* Out of line. */
 #include <strings.h>
-
-int ffs(int x) {
-  return __builtin_ffs(x);
-}
diff --git a/libc/include/android/legacy_strings_inlines.h b/libc/include/android/legacy_strings_inlines.h
deleted file mode 100644
index 2cc2da2..0000000
--- a/libc/include/android/legacy_strings_inlines.h
+++ /dev/null
@@ -1,44 +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 defined(__i386__) && __ANDROID_API__ < 18
-
-#include <strings.h>
-
-__BEGIN_DECLS
-
-/* Everyone except x86 had ffs since the beginning. */
-static __inline int ffs(int __n) { return __builtin_ffs(__n); }
-
-__END_DECLS
-
-#endif
diff --git a/libc/include/strings.h b/libc/include/strings.h
index 08c2326..ba69c8d 100644
--- a/libc/include/strings.h
+++ b/libc/include/strings.h
@@ -49,6 +49,10 @@
 
 #include <bits/strcasecmp.h>
 
+#if !defined(__BIONIC_STRINGS_INLINE)
+#define __BIONIC_STRINGS_INLINE static __inline
+#endif
+
 __BEGIN_DECLS
 
 /** Deprecated. Use memmove() instead. */
@@ -63,19 +67,41 @@
   __builtin_memset(b, 0, len);
 }
 
-#if !defined(__i386__) || __ANDROID_API__ >= 18
 /**
- * [ffs(3)](http://man7.org/linux/man-pages/man3/ffs.3.html) finds the first set bit in `__i`.
+ * [ffs(3)](http://man7.org/linux/man-pages/man3/ffs.3.html) finds the
+ * first set bit in `__n`.
  *
- * Returns 0 if no bit is set, or the index of the lowest set bit (counting from 1) otherwise.
+ * Returns 0 if no bit is set, or the index of the lowest set bit (counting
+ * from 1) otherwise.
  */
-int ffs(int __i) __INTRODUCED_IN_X86(18);
-#endif
+__BIONIC_STRINGS_INLINE int ffs(int __n) {
+  return __builtin_ffs(__n);
+}
+
+/**
+ * [ffsl(3)](http://man7.org/linux/man-pages/man3/ffsl.3.html) finds the
+ * first set bit in `__n`.
+ *
+ * Returns 0 if no bit is set, or the index of the lowest set bit (counting
+ * from 1) otherwise.
+ */
+__BIONIC_STRINGS_INLINE int ffsl(long __n) {
+  return __builtin_ffsl(__n);
+}
+
+/**
+ * [ffsll(3)](http://man7.org/linux/man-pages/man3/ffsll.3.html) finds the
+ * first set bit in `__n`.
+ *
+ * Returns 0 if no bit is set, or the index of the lowest set bit (counting
+ * from 1) otherwise.
+ */
+__BIONIC_STRINGS_INLINE int ffsll(long long __n) {
+  return __builtin_ffsll(__n);
+}
 
 #if defined(__BIONIC_INCLUDE_FORTIFY_HEADERS)
 #include <bits/fortify/strings.h>
 #endif
 
 __END_DECLS
-
-#include <android/legacy_strings_inlines.h>
diff --git a/libc/libc.map.txt b/libc/libc.map.txt
index 4bfb8a2..2284775 100644
--- a/libc/libc.map.txt
+++ b/libc/libc.map.txt
@@ -1550,6 +1550,12 @@
     _Unwind_VRS_Set; # apex llndk arm
 } LIBC_Q;
 
+LIBC_S { # introduced=31
+  global:
+    ffsl;
+    ffsll;
+} LIBC_R;
+
 LIBC_PRIVATE {
   global:
     __accept4; # arm x86