diff --git a/libc/include/.clang-format b/libc/include/.clang-format
new file mode 100644
index 0000000..e384528
--- /dev/null
+++ b/libc/include/.clang-format
@@ -0,0 +1 @@
+DisableFormat: true
diff --git a/libc/include/bits/flock.h b/libc/include/bits/flock.h
new file mode 100644
index 0000000..7c452ad
--- /dev/null
+++ b/libc/include/bits/flock.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2020 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
+
+/**
+ * @file bits/flock.h
+ * @brief struct flock.
+ */
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+__BEGIN_DECLS
+
+#define __FLOCK64_BODY \
+  short l_type; \
+  short l_whence; \
+  off64_t l_start; \
+  off64_t l_len; \
+  pid_t l_pid; \
+
+#if defined(__USE_FILE_OFFSET64) || defined(__LP64__)
+#define __FLOCK_BODY __FLOCK64_BODY
+#else
+#define __FLOCK_BODY \
+  short l_type; \
+  short l_whence; \
+  off_t l_start; \
+  off_t l_len; \
+  pid_t l_pid; \
+
+#endif
+
+struct flock { __FLOCK_BODY };
+struct flock64 { __FLOCK64_BODY };
+
+#undef __FLOCK_BODY
+#undef __FLOCK64_BODY
+
+__END_DECLS
diff --git a/libc/include/bits/flock64.h b/libc/include/bits/flock64.h
new file mode 100644
index 0000000..95500b9
--- /dev/null
+++ b/libc/include/bits/flock64.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2020 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
+
+/* Empty. */
diff --git a/libc/include/fcntl.h b/libc/include/fcntl.h
index 23a58d6..1ea94e6 100644
--- a/libc/include/fcntl.h
+++ b/libc/include/fcntl.h
@@ -51,14 +51,32 @@
 
 __BEGIN_DECLS
 
-#ifdef __LP64__
+#if defined(__LP64__)
+
 /* LP64 kernels don't have F_*64 defines because their flock is 64-bit. */
+
 /** Flag for flock(). */
 #define F_GETLK64  F_GETLK
 /** Flag for flock(). */
 #define F_SETLK64  F_SETLK
 /** Flag for flock(). */
 #define F_SETLKW64 F_SETLKW
+
+#elif defined(__USE_FILE_OFFSET64)
+
+/* For _FILE_OFFSET_BITS=64, redirect the constants to the off64_t variants. */
+
+#undef F_GETLK
+#undef F_SETLK
+#undef F_SETLKW
+
+/** Flag for flock(). */
+#define F_GETLK F_GETLK64
+/** Flag for flock(). */
+#define F_SETLK F_SETLK64
+/** Flag for flock(). */
+#define F_SETLKW F_SETLKW64
+
 #endif
 
 /** Flag for open(). */