}

// #undef processing
func (in *Input) undef() {
	name := in.macroName()
	if in.macros[name] == nil {
		in.Error("#undef for undefined macro:", name)
	}
	// Newline must be next.
	tok := in.Stack.Next()
	if tok != '\n' {
		in.Error("syntax error in #undef for macro:", name)
	}
	delete(in.macros, name)
}

index d1cb3dd..30482a1 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -423,4 +423,14 @@
 # endif
 #endif
 
+/* Undefine (also defined in libc-symbols.h).  */
+#undef __attribute_copy__
+#if __GNUC_PREREQ (9, 0)
+/* Copies attributes from the declaration or type referenced by
+   the argument.  */
+# define __attribute_copy__(arg) __attribute__ ((__copy__ (arg)))
+#else

-   <http://www.gnu.org/licenses/>.  */
+   <https://www.gnu.org/licenses/>.  */
 
 #include <string.h>
 
-#ifdef _LIBC
-# include <memcopy.h>
-#endif
-
 #ifndef STRNCAT
 # undef strncat
 # define STRNCAT  strncat
@@ -29,54 +25,16 @@
 char *
 STRNCAT (char *s1, const char *s2, size_t n)
 {
-  char c;
   char *s = s1;
 
   /* Find the end of S1.  */
-  do

	MOVD	F4, 1(F5)		// a404c02b
	MOVW	R4, F5			// 85a41401
	MOVW	F4, R5			// 85b41401
	MOVV	R4, F5			// 85a81401
	MOVV	F4, R5			// 85b81401
	WORD	$74565			// 45230100
	BREAK				// 00002a00
	UNDEF				// 00002a00

	ANDN	R4, R5, R6		// a6901600
	ANDN	R4, R5			// a5901600
	ORN	R4, R5, R6		// a6101600
	ORN	R4, R5			// a5101600

	// mul
	MUL	R4, R5	  		// a5101c00
	MUL	R4, R5, R6	  	// a6101c00

/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,

	LTEBR	F1, F2                 // b3020021
	LTDBR	F3, F4                 // b3120043
	TCEB	F5, $8                 // ed5000080010
	TCDB	F15, $4095             // edf00fff0011

	UNDEF                          // 00000000
	BRRK			       // 0001
	NOPH                           // 0700

	SYNC                           // 07e0

	KM	R2, R4                 // b92e0024

/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,

/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,

/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,

/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,