diff --git a/libc/include/sys/cdefs.h b/libc/include/sys/cdefs.h
index 6f238a9..21d59fa 100644
--- a/libc/include/sys/cdefs.h
+++ b/libc/include/sys/cdefs.h
@@ -77,7 +77,9 @@
 #define	__GNUC_PREREQ(x, y)	0
 #endif
 
-#include <sys/cdefs_elf.h>
+#define __strong_alias(alias, sym) \
+    __asm__(".global " #alias "\n" \
+            #alias " = " #sym);
 
 #if defined(__cplusplus)
 #define	__BEGIN_DECLS		extern "C" {
@@ -263,13 +265,6 @@
 #endif
 #endif /* !(__STDC_VERSION__ >= 199901L) */
 
-#if defined(_KERNEL)
-#if defined(NO_KERNEL_RCSIDS)
-#undef __KERNEL_RCSID
-#define	__KERNEL_RCSID(_n, _s)		/* nothing */
-#endif /* NO_KERNEL_RCSIDS */
-#endif /* _KERNEL */
-
 /*
  * A barrier to stop the optimizer from moving code or assume live
  * register values. This is gcc specific, the version is more or less
diff --git a/libc/include/sys/cdefs_elf.h b/libc/include/sys/cdefs_elf.h
deleted file mode 100644
index a40a867..0000000
--- a/libc/include/sys/cdefs_elf.h
+++ /dev/null
@@ -1,43 +0,0 @@
-/*	$NetBSD: cdefs_elf.h,v 1.22 2005/02/26 22:25:34 perry Exp $	*/
-
-/*
- * Copyright (c) 1995, 1996 Carnegie-Mellon University.
- * All rights reserved.
- *
- * Author: Chris G. Demetriou
- *
- * Permission to use, copy, modify and distribute this software and
- * its documentation is hereby granted, provided that both the copyright
- * notice and this permission notice appear in all copies of the
- * software, derivative works or modified versions, and any portions
- * thereof, and that both notices appear in supporting documentation.
- *
- * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
- * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
- * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
- *
- * Carnegie Mellon requests users of this software to return to
- *
- *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
- *  School of Computer Science
- *  Carnegie Mellon University
- *  Pittsburgh PA 15213-3890
- *
- * any improvements or extensions that they make and grant Carnegie the
- * rights to redistribute these changes.
- */
-
-#ifndef _SYS_CDEFS_ELF_H_
-#define	_SYS_CDEFS_ELF_H_
-
-#define __strong_alias(alias, sym) \
-    __asm__(".global " #alias "\n" \
-            #alias " = " #sym);
-
-/* We use __warnattr instead of __warn_references.
- * TODO: remove this and put an empty definition in one of the upstream-* compatibility headers.
- */
-#define	__warn_references(sym,msg)					\
-    /*__asm__(".section .gnu.warning." #sym "\n\t.ascii \"" msg "\"\n\t.text");*/
-
-#endif /* !_SYS_CDEFS_ELF_H_ */
diff --git a/libc/upstream-openbsd/android/include/openbsd-compat.h b/libc/upstream-openbsd/android/include/openbsd-compat.h
index 8386ba5..8783467 100644
--- a/libc/upstream-openbsd/android/include/openbsd-compat.h
+++ b/libc/upstream-openbsd/android/include/openbsd-compat.h
@@ -35,6 +35,9 @@
 /* Ignore all __weak_alias in OpenBSD. */
 #define __weak_alias(alias,sym)
 
+/* Ignore all __warn_references in OpenBSD. */
+#define __warn_references(sym,msg)
+
 /* OpenBSD's <ctype.h> uses these names, which conflicted with stlport.
  * Additionally, we changed the numeric/digit type from N to D for libcxx.
  */
diff --git a/libm/freebsd-compat.h b/libm/freebsd-compat.h
index 1481cc2..a4dd6c2 100644
--- a/libm/freebsd-compat.h
+++ b/libm/freebsd-compat.h
@@ -26,6 +26,8 @@
 #define __strong_reference(sym,aliassym) \
     extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym)))
 
+#define __warn_references(sym,msg) /* ignored */
+
 /* digittoint is in BSD's <ctype.h>. */
 int digittoint(char ch);