diff -u ctags-5.8.orig/c.c ctags-5.8/c.c
--- ctags-5.8.orig/c.c	2021-09-27 10:44:24.772898854 +0200
+++ ctags-5.8/c.c	2021-09-27 10:58:15.168499970 +0200
@@ -624,7 +624,7 @@
 	return name;
 }
 
-static void __unused__ pt (tokenInfo *const token)
+static void __maybe_unused__ pt (tokenInfo *const token)
 {
 	if (isType (token, TOKEN_NAME))
 		printf ("type: %-12s: %-13s   line: %lu\n",
@@ -639,7 +639,7 @@
 			tokenString (token->type), token->lineNumber);
 }
 
-static void __unused__ ps (statementInfo *const st)
+static void __maybe_unused__ ps (statementInfo *const st)
 {
 	unsigned int i;
 	printf ("scope: %s   decl: %s   gotName: %s   gotParenName: %s isPointer: %s\n",
diff -u ctags-5.8.orig/eiffel.c ctags-5.8/eiffel.c
--- ctags-5.8.orig/eiffel.c	2021-09-27 10:44:24.732898295 +0200
+++ ctags-5.8/eiffel.c	2021-09-27 10:58:15.168499970 +0200
@@ -807,7 +807,7 @@
 
 static boolean parseType (tokenInfo *const token);
 
-static void parseGeneric (tokenInfo *const token, boolean declaration __unused__)
+static void parseGeneric (tokenInfo *const token, boolean declaration __maybe_unused__)
 {
 	unsigned int depth = 0;
 #ifdef TYPE_REFERENCE_TOOL
diff -u ctags-5.8.orig/general.h ctags-5.8/general.h
--- ctags-5.8.orig/general.h	2007-05-03 05:21:08.000000000 +0200
+++ ctags-5.8/general.h	2021-09-27 10:57:03.851490665 +0200
@@ -57,10 +57,10 @@
  *  to prevent warnings about unused variables.
  */
 #if (__GNUC__ > 2  ||  (__GNUC__ == 2  &&  __GNUC_MINOR__ >= 7)) && !defined (__GNUG__)
-# define __unused__  __attribute__((unused))
+# define __maybe_unused__  __attribute__((unused))
 # define __printf__(s,f)  __attribute__((format (printf, s, f)))
 #else
-# define __unused__
+# define __maybe_unused__
 # define __printf__(s,f)
 #endif
 
Common subdirectories: ctags-5.8.orig/gnu_regex and ctags-5.8/gnu_regex
diff -u ctags-5.8.orig/lregex.c ctags-5.8/lregex.c
--- ctags-5.8.orig/lregex.c	2021-09-27 10:44:24.732898295 +0200
+++ ctags-5.8/lregex.c	2021-09-27 10:58:15.176500083 +0200
@@ -538,11 +538,11 @@
 #endif  /* HAVE_REGEX */
 
 extern void addTagRegex (
-		const langType language __unused__,
-		const char* const regex __unused__,
-		const char* const name __unused__,
-		const char* const kinds __unused__,
-		const char* const flags __unused__)
+		const langType language __maybe_unused__,
+		const char* const regex __maybe_unused__,
+		const char* const name __maybe_unused__,
+		const char* const kinds __maybe_unused__,
+		const char* const flags __maybe_unused__)
 {
 #ifdef HAVE_REGEX
 	Assert (regex != NULL);
@@ -564,10 +564,10 @@
 }
 
 extern void addCallbackRegex (
-		const langType language __unused__,
-		const char* const regex __unused__,
-		const char* const flags __unused__,
-		const regexCallback callback __unused__)
+		const langType language __maybe_unused__,
+		const char* const regex __maybe_unused__,
+		const char* const flags __maybe_unused__,
+		const regexCallback callback __maybe_unused__)
 {
 #ifdef HAVE_REGEX
 	Assert (regex != NULL);
@@ -581,7 +581,7 @@
 }
 
 extern void addLanguageRegex (
-		const langType language __unused__, const char* const regex __unused__)
+		const langType language __maybe_unused__, const char* const regex __maybe_unused__)
 {
 #ifdef HAVE_REGEX
 	if (! regexBroken)
@@ -602,7 +602,7 @@
 */
 
 extern boolean processRegexOption (const char *const option,
-								   const char *const parameter __unused__)
+								   const char *const parameter __maybe_unused__)
 {
 	boolean handled = FALSE;
 	const char* const dash = strchr (option, '-');
@@ -624,7 +624,7 @@
 	return handled;
 }
 
-extern void disableRegexKinds (const langType language __unused__)
+extern void disableRegexKinds (const langType language __maybe_unused__)
 {
 #ifdef HAVE_REGEX
 	if (language <= SetUpper  &&  Sets [language].count > 0)
@@ -639,8 +639,8 @@
 }
 
 extern boolean enableRegexKind (
-		const langType language __unused__,
-		const int kind __unused__, const boolean mode __unused__)
+		const langType language __maybe_unused__,
+		const int kind __maybe_unused__, const boolean mode __maybe_unused__)
 {
 	boolean result = FALSE;
 #ifdef HAVE_REGEX
@@ -660,7 +660,7 @@
 	return result;
 }
 
-extern void printRegexKinds (const langType language __unused__, boolean indent __unused__)
+extern void printRegexKinds (const langType language __maybe_unused__, boolean indent __maybe_unused__)
 {
 #ifdef HAVE_REGEX
 	if (language <= SetUpper  &&  Sets [language].count > 0)
diff -u ctags-5.8.orig/lua.c ctags-5.8/lua.c
--- ctags-5.8.orig/lua.c	2006-10-12 05:26:40.000000000 +0200
+++ ctags-5.8/lua.c	2021-09-27 10:58:15.176500083 +0200
@@ -37,7 +37,7 @@
 */
 
 /* for debugging purposes */
-static void __unused__ print_string (char *p, char *q)
+static void __maybe_unused__ print_string (char *p, char *q)
 {
 	for ( ; p != q; p++)
 		fprintf (errout, "%c", *p);
diff -u ctags-5.8.orig/main.c ctags-5.8/main.c
--- ctags-5.8.orig/main.c	2021-09-27 10:44:24.784899021 +0200
+++ ctags-5.8/main.c	2021-09-27 10:58:15.176500083 +0200
@@ -511,7 +511,7 @@
  *		Start up code
  */
 
-extern int main (int __unused__ argc, char **argv)
+extern int main (int __maybe_unused__ argc, char **argv)
 {
 	cookedArgs *args;
 #ifdef VMS
diff -u ctags-5.8.orig/options.c ctags-5.8/options.c
--- ctags-5.8.orig/options.c	2021-09-27 10:44:24.784899021 +0200
+++ ctags-5.8/options.c	2021-09-27 10:58:15.180500140 +0200
@@ -731,7 +731,7 @@
 }
 
 static void processExcludeOption (
-		const char *const option __unused__, const char *const parameter)
+		const char *const option __maybe_unused__, const char *const parameter)
 {
 	const char *const fileName = parameter + 1;
 	if (parameter [0] == '\0')
@@ -869,7 +869,7 @@
 }
 
 static void processFilterTerminatorOption (
-		const char *const option __unused__, const char *const parameter)
+		const char *const option __maybe_unused__, const char *const parameter)
 {
 	freeString (&Option.filterTerminator);
 	Option.filterTerminator = stringCopy (parameter);
@@ -931,8 +931,8 @@
 }
 
 static void processHelpOption (
-		const char *const option __unused__,
-		const char *const parameter __unused__)
+		const char *const option __maybe_unused__,
+		const char *const parameter __maybe_unused__)
 {
 	printProgramIdentification ();
 	putchar ('\n');
@@ -1140,8 +1140,8 @@
 }
 
 static void processLicenseOption (
-		const char *const option __unused__,
-		const char *const parameter __unused__)
+		const char *const option __maybe_unused__,
+		const char *const parameter __maybe_unused__)
 {
 	printProgramIdentification ();
 	puts ("");
@@ -1167,8 +1167,8 @@
 }
 
 static void processListMapsOption (
-		const char *const __unused__ option,
-		const char *const __unused__ parameter)
+		const char *const __maybe_unused__ option,
+		const char *const __maybe_unused__ parameter)
 {
 	if (parameter [0] == '\0' || strcasecmp (parameter, "all") == 0)
 	    printLanguageMaps (LANG_AUTO);
@@ -1184,8 +1184,8 @@
 }
 
 static void processListLanguagesOption (
-		const char *const option __unused__,
-		const char *const parameter __unused__)
+		const char *const option __maybe_unused__,
+		const char *const parameter __maybe_unused__)
 {
 	printLanguageList ();
 	exit (0);
@@ -1359,8 +1359,8 @@
 }
 
 static void processVersionOption (
-		const char *const option __unused__,
-		const char *const parameter __unused__)
+		const char *const option __maybe_unused__,
+		const char *const parameter __maybe_unused__)
 {
 	printProgramIdentification ();
 	exit (0);
diff -u ctags-5.8.orig/parse.c ctags-5.8/parse.c
--- ctags-5.8.orig/parse.c	2007-07-31 07:35:33.000000000 +0200
+++ ctags-5.8/parse.c	2021-09-27 10:58:15.180500140 +0200
@@ -376,7 +376,7 @@
 */
 
 extern void processLanguageDefineOption (
-		const char *const option, const char *const parameter __unused__)
+		const char *const option, const char *const parameter __maybe_unused__)
 {
 #ifdef HAVE_REGEX
 	if (parameter [0] == '\0')
diff -u ctags-5.8.orig/python.c ctags-5.8/python.c
--- ctags-5.8.orig/python.c	2021-09-27 10:44:24.736898351 +0200
+++ ctags-5.8/python.c	2021-09-27 10:58:15.180500140 +0200
@@ -135,7 +135,7 @@
  * extract all relevant information and create a tag.
  */
 static void makeFunctionTag (vString *const function,
-	vString *const parent, int is_class_parent, const char *arglist __unused__)
+	vString *const parent, int is_class_parent, const char *arglist __maybe_unused__)
 {
 	tagEntryInfo tag;
 	initTagEntry (&tag, vStringValue (function));
diff -u ctags-5.8.orig/routines.c ctags-5.8/routines.c
--- ctags-5.8.orig/routines.c	2007-06-07 06:35:21.000000000 +0200
+++ ctags-5.8/routines.c	2021-09-27 10:58:15.184500196 +0200
@@ -526,7 +526,7 @@
 
 #if ! defined (HAVE_STAT_ST_INO)
 
-static void canonicalizePath (char *const path __unused__)
+static void canonicalizePath (char *const path __maybe_unused__)
 {
 #if defined (MSDOS_STYLE_PATH)
 	char *p;