C23 defines bool stuff as keywords. Use stdbool.h and make things
work with gcc15 by default.


diff -ru libsndfile-1.2.2/src/ALAC/alac_decoder.c libsndfile-1.2.2.fix/src/ALAC/alac_decoder.c
--- libsndfile-1.2.2/src/ALAC/alac_decoder.c	2021-05-17 11:12:28.000000000 +0200
+++ libsndfile-1.2.2.fix/src/ALAC/alac_decoder.c	2025-06-01 15:13:38.288859954 +0200
@@ -27,6 +27,7 @@
 #include <stdlib.h>
 #include <stddef.h>
 #include <string.h>
+#include <stdbool.h>
 
 #include "alac_codec.h"
 
@@ -38,11 +39,6 @@
 #include "ALACBitUtilities.h"
 #include "EndianPortable.h"
 
-typedef enum
-{	false = 0,
-	true = 1
-} bool ;
-
 // constants/data
 const uint32_t kMaxBitDepth = 32 ;			// max allowed bit depth is 32
 
diff -ru libsndfile-1.2.2/src/ALAC/alac_encoder.c libsndfile-1.2.2.fix/src/ALAC/alac_encoder.c
--- libsndfile-1.2.2/src/ALAC/alac_encoder.c	2021-05-17 11:12:28.000000000 +0200
+++ libsndfile-1.2.2.fix/src/ALAC/alac_encoder.c	2025-06-01 15:11:42.906859968 +0200
@@ -31,6 +31,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdbool.h>
 
 #include "sfendian.h"
 
@@ -44,12 +45,6 @@
 #include "ALACAudioTypes.h"
 #include "EndianPortable.h"
 
-typedef enum
-{
-	false = 0,
-	true = 1
-} bool ;
-
 static void	GetConfig (ALAC_ENCODER *p, ALACSpecificConfig * config) ;
 
 static int32_t	EncodeStereo (ALAC_ENCODER *p, struct BitBuffer * bitstream, const int32_t * input, uint32_t stride, uint32_t channelIndex, uint32_t numSamples) ;