fix c23 https://bugs.gentoo.org/943815
apply fix from Fedora https://src.fedoraproject.org/rpms/shntool/raw/fc11294/f/gcc-15-fixes.patch
--- a/include/format.h
+++ b/include/format.h
@@ -35,7 +35,7 @@ void tagcpy(unsigned char *,unsigned char *);
 int tagcmp(unsigned char *,unsigned char *);
 
 /* function to check if a file name is about to be clobbered, and if so, asks whether this is OK */
-int clobber_check(char *);
+bool clobber_check(char *);
 
 /* find an output format module with the given name */
 format_module *find_format(char *);
--- a/include/mode.h
+++ b/include/mode.h
@@ -78,7 +78,7 @@ void create_output_filename(char *,char *,char *);
 FILE *open_output_stream(char *,proc_info *);
 
 /* function to determine if two filenames point to the same file */
-int files_are_identical(char *,char *);
+bool files_are_identical(char *,char *);
 
 /* function to remove a file if it exists */
 void remove_file(char *);
--- a/include/module-types.h
+++ b/include/module-types.h
@@ -23,6 +23,8 @@
 #ifndef __MODULE_TYPES_H__
 #define __MODULE_TYPES_H__
 
+#include <stdbool.h>
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -44,9 +46,6 @@
 #define PATHSEPCHAR '/'
 #endif
 
-/* boolean type */
-typedef int bool;
-
 /* wtypes */
 typedef unsigned long wlong;
 typedef unsigned short wshort;
--- a/src/core_mode.c
+++ b/src/core_mode.c
@@ -564,18 +564,12 @@ static int compare_ascii(const wave_info **w1,const wave_info **w2)
 
 static void ascii_sort_files(wave_info **filenames, int numfiles)
 {
-  int (*cmpfunc) ();
-
-  cmpfunc = compare_ascii;
-  qsort(filenames,numfiles,sizeof(wave_info *),cmpfunc);
+  qsort(filenames,numfiles,sizeof(wave_info *),(int (*)(const void*, const void*))compare_ascii);
 }
 
 static void version_sort_files(wave_info **filenames,int numfiles)
 {
-  int (*cmpfunc) ();
-
-  cmpfunc = compare_version;
-  qsort(filenames,numfiles,sizeof(wave_info *),cmpfunc);
+  qsort(filenames,numfiles,sizeof(wave_info *),(int (*)(const void*, const void*))compare_version);
 }
 
 /* public functions */
-- 
2.48.1