diff --git a/libc/arch-arm/include/machine/cdefs.h b/libc/arch-arm/include/machine/cdefs.h
deleted file mode 100644
index 44f1542d6..000000000
--- a/libc/arch-arm/include/machine/cdefs.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/*	$OpenBSD: cdefs.h,v 1.2 2005/11/24 20:46:44 deraadt Exp $	*/
-
-#ifndef	_MACHINE_CDEFS_H_
-#define	_MACHINE_CDEFS_H_
-
-#if defined(lint)
-#define __indr_reference(sym,alias)	__lint_equal__(sym,alias)
-#define __warn_references(sym,msg)
-#define __weak_alias(alias,sym)		__lint_equal__(sym,alias)
-#elif defined(__GNUC__) && defined(__STDC__)
-#define __weak_alias(alias,sym)					\
-	__asm__(".weak " __STRING(alias) " ; " __STRING(alias)	\
-	    " = " __STRING(sym));
-#define	__warn_references(sym,msg)				\
-	__asm__(".section .gnu.warning." __STRING(sym)		\
-	    " ; .ascii \"" msg "\" ; .text");
-#endif
-
-#endif /* !_MACHINE_CDEFS_H_ */
diff --git a/libc/arch-mips/include/machine/cdefs.h b/libc/arch-mips/include/machine/cdefs.h
deleted file mode 100644
index d52376ae1..000000000
--- a/libc/arch-mips/include/machine/cdefs.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/*	$OpenBSD: cdefs.h,v 1.4 2006/01/10 00:04:04 millert Exp $	*/
-
-/*
- * Copyright (c) 2002-2003 Opsycon AB  (www.opsycon.se / www.opsycon.com)
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. 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 AUTHOR ``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 AUTHOR 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.
- *
- */
-
-
-#ifndef _MIPS_CDEFS_H_
-#define	_MIPS_CDEFS_H_
-
-#if defined(lint)
-#define __indr_reference(sym,alias)	__lint_equal__(sym,alias)
-#define __warn_references(sym,msg)
-#define __weak_alias(alias,sym)		__lint_equal__(sym,alias)
-#elif defined(__GNUC__) && defined(__STDC__)
-#define __weak_alias(alias,sym)				\
-	__asm__(".weak " __STRING(alias) " ; "		\
-	    __STRING(alias) " = " __STRING(sym))
-#define	__warn_references(sym,msg)			\
-	__asm__(".section .gnu.warning." __STRING(sym)	\
-	    " ; .ascii \"" msg "\" ; .text")
-#define	__indr_references(sym,msg)	/* nothing */
-#endif
-
-#endif /* !_MIPS_CDEFS_H_ */
diff --git a/libc/arch-x86/include/machine/cdefs.h b/libc/arch-x86/include/machine/cdefs.h
deleted file mode 100644
index 6efee6ac4..000000000
--- a/libc/arch-x86/include/machine/cdefs.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/*	$OpenBSD: cdefs.h,v 1.9 2005/11/24 20:46:45 deraadt Exp $	*/
-
-/*
- * Written by J.T. Conklin <jtc@wimsey.com> 01/17/95.
- * Public domain.
- */
-
-#ifndef	_MACHINE_CDEFS_H_
-#define	_MACHINE_CDEFS_H_
-
-#if defined(lint)
-#define __indr_reference(sym,alias)	__lint_equal__(sym,alias)
-#define __warn_references(sym,msg)
-#define __weak_alias(alias,sym)		__lint_equal__(sym,alias)
-#elif defined(__GNUC__) && defined(__STDC__)
-#define __weak_alias(alias,sym)				\
-	__asm__(".weak " __STRING(alias) " ; "		\
-	    __STRING(alias) " = " __STRING(sym));
-#define __warn_references(sym,msg)			\
-	__asm__(".section .gnu.warning." __STRING(sym)	\
-	    " ; .ascii \"" msg "\" ; .text");
-#endif
-
-#endif /* !_MACHINE_CDEFS_H_ */
diff --git a/libc/arch-x86_64/include/machine/cdefs.h b/libc/arch-x86_64/include/machine/cdefs.h
deleted file mode 100644
index eb243a33d..000000000
--- a/libc/arch-x86_64/include/machine/cdefs.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/*	$OpenBSD: cdefs.h,v 1.3 2013/03/28 17:30:45 martynas Exp $	*/
-
-/*
- * Written by J.T. Conklin <jtc@wimsey.com> 01/17/95.
- * Public domain.
- */
-
-#ifndef	_MACHINE_CDEFS_H_
-#define	_MACHINE_CDEFS_H_
-
-#define __strong_alias(alias,sym)					\
-	__asm__(".global " __STRING(alias) " ; " __STRING(alias)	\
-	    " = " __STRING(sym))
-#define __weak_alias(alias,sym)						\
-	__asm__(".weak " __STRING(alias) " ; " __STRING(alias)		\
-	    " = " __STRING(sym))
-#define __warn_references(sym,msg)					\
-	__asm__(".section .gnu.warning." __STRING(sym)			\
-	    " ; .ascii \"" msg "\" ; .text")
-
-#endif /* !_MACHINE_CDEFS_H_ */
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 409afeaf8..260a4e706 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -222,13 +222,13 @@ int	 getchar(void);
 ssize_t	 getdelim(char ** __restrict, size_t * __restrict, int,
 	    FILE * __restrict);
 ssize_t	 getline(char ** __restrict, size_t * __restrict, FILE * __restrict);
-char	*gets(char *);
+
 #if __BSD_VISIBLE && !defined(__SYS_ERRLIST)
 #define __SYS_ERRLIST
-
 extern int sys_nerr;			/* perror(3) external variables */
 extern char *sys_errlist[];
 #endif
+
 void	 perror(const char *);
 int	 printf(const char * __restrict, ...)
 		__printflike(1, 2);
@@ -251,13 +251,16 @@ int	 vprintf(const char * __restrict, __va_list)
 		__printflike(1, 0);
 
 #ifndef __AUDIT__
-char	*gets(char *);
-int	 sprintf(char * __restrict, const char * __restrict, ...)
-		__printflike(2, 3);
-char	*tmpnam(char *);
-int	 vsprintf(char * __restrict, const char * __restrict,
-    __va_list)
-		__printflike(2, 0);
+char* gets(char*) __warnattr("gets is very unsafe; consider using fgets");
+int sprintf(char* __restrict, const char* __restrict, ...)
+    __printflike(2, 3) __warnattr("sprintf is often misused; please use snprintf");
+char* tmpnam(char*) __warnattr("tmpnam possibly used unsafely; consider using mkstemp");
+int vsprintf(char* __restrict, const char* __restrict, __va_list)
+    __printflike(2, 0) __warnattr("vsprintf is often misused; please use vsnprintf");
+#if __XPG_VISIBLE
+char* tempnam(const char*, const char*)
+    __warnattr("tempnam possibly used unsafely; consider using mkstemp");
+#endif
 #endif
 
 extern int rename(const char*, const char*);
@@ -320,9 +323,6 @@ int	 putc_unlocked(int, FILE *);
 int	 putchar_unlocked(int);
 #endif /* __POSIX_VISIBLE >= 199506 */
 
-#if __XPG_VISIBLE
-char	*tempnam(const char *, const char *);
-#endif
 __END_DECLS
 
 #endif /* __BSD_VISIBLE || __POSIX_VISIBLE || __XPG_VISIBLE */
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 9fa84c1d3..72b554fd4 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -51,9 +51,9 @@ extern int setenv(const char *, const char *, int);
 extern int unsetenv(const char *);
 extern int clearenv(void);
 
-extern char *mkdtemp(char *);
-extern char *mktemp(char *);
-extern int mkstemp(char *);
+extern char* mkdtemp(char*);
+extern char* mktemp(char*) __warnattr("mktemp possibly used unsafely; consider using mkstemp");
+extern int mkstemp(char*);
 
 extern long strtol(const char *, char **, int);
 extern long long strtoll(const char *, char **, int);
diff --git a/libc/include/sys/cdefs.h b/libc/include/sys/cdefs.h
index c7f2ac7ac..b4dad74f8 100644
--- a/libc/include/sys/cdefs.h
+++ b/libc/include/sys/cdefs.h
@@ -334,8 +334,10 @@
 
 #if __GNUC_PREREQ__(4, 3)
 #define __errordecl(name, msg) extern void name(void) __attribute__((__error__(msg)))
+#define __warnattr(msg) __attribute__((__warning__(msg)))
 #else
 #define __errordecl(name, msg) extern void name(void)
+#define __warnattr(msg)
 #endif
 
 /*
diff --git a/libc/include/sys/cdefs_elf.h b/libc/include/sys/cdefs_elf.h
index 0887fa57b..bb846b7fd 100644
--- a/libc/include/sys/cdefs_elf.h
+++ b/libc/include/sys/cdefs_elf.h
@@ -38,20 +38,10 @@
 #define _C_LABEL_STRING(x)	x
 #endif
 
-#if __STDC__
 #define	___RENAME(x)	__asm__(___STRING(_C_LABEL(x)))
-#else
-#ifdef __LEADING_UNDERSCORE
-#define	___RENAME(x)	____RENAME(_/**/x)
-#define	____RENAME(x)	__asm__(___STRING(x))
-#else
-#define	___RENAME(x)	__asm__(___STRING(x))
-#endif
-#endif
 
 #define	__indr_reference(sym,alias)	/* nada, since we do weak refs */
 
-#if __STDC__
 #define	__strong_alias(alias,sym)	       				\
     __asm__(".global " _C_LABEL_STRING(#alias) "\n"			\
 	    _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym));
@@ -61,39 +51,15 @@
 	    _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym));
 #define	__weak_extern(sym)						\
     __asm__(".weak " _C_LABEL_STRING(#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");
+    /*__asm__(".section .gnu.warning." #sym "\n\t.ascii \"" msg "\"\n\t.text");*/
 
-#else /* !__STDC__ */
-
-#ifdef __LEADING_UNDERSCORE
-#define __weak_alias(alias,sym) ___weak_alias(_/**/alias,_/**/sym)
-#define	___weak_alias(alias,sym)					\
-    __asm__(".weak alias\nalias = sym");
-#else
-#define	__weak_alias(alias,sym)						\
-    __asm__(".weak alias\nalias = sym");
-#endif
-#ifdef __LEADING_UNDERSCORE
-#define __weak_extern(sym) ___weak_extern(_/**/sym)
-#define	___weak_extern(sym)						\
-    __asm__(".weak sym");
-#else
-#define	__weak_extern(sym)						\
-    __asm__(".weak sym");
-#endif
-#define	__warn_references(sym,msg)					\
-    __asm__(".section .gnu.warning.sym\n\t.ascii msg ; .text");
-
-#endif /* !__STDC__ */
-
-#if __STDC__
 #define	__SECTIONSTRING(_sec, _str)					\
 	__asm__(".section " #_sec "\n\t.asciz \"" _str "\"\n\t.previous")
-#else
-#define	__SECTIONSTRING(_sec, _str)					\
-	__asm__(".section _sec\n\t.asciz _str\n\t.previous")
-#endif
 
 /* GCC visibility helper macro */
 /* This must be used to tag non-static functions that are private, i.e.