https://bugs.gentoo.org/921126
Fix for incompatible pointer types: Just upsize the size
everywhere it's used, so it fits in largest, gsize
diff -ru a/blib/bpacket.c a/blib/bpacket.c
--- a/blib/bpacket.c	2025-01-09 18:10:29.298407575 +0400
+++ a/blib/bpacket.c	2025-01-09 18:13:09.318508466 +0400
@@ -48,10 +48,10 @@
               gint  height,
               gint  channels,
               gint  maxval,
-              gint *data_size)
+              gsize *data_size)
 {
   BPacket *packet;
-  gint     size;
+  gsize     size;
 
   g_return_val_if_fail (width > 0, NULL);
   g_return_val_if_fail (height > 0, NULL);
diff -ru a/blib/bpacket.h a/blib/bpacket.h
--- a/blib/bpacket.h	2025-01-09 18:10:29.297407580 +0400
+++ a/blib/bpacket.h	2025-01-09 18:12:22.749770123 +0400
@@ -42,7 +42,7 @@
 			 gint     height,
 			 gint     channels,
 			 gint     maxval,
-			 gint    *data_size);
+			 gsize    *data_size);
 gsize     b_packet_size (BPacket *packet);
 void      b_packet_hton (BPacket *packet);
 void      b_packet_ntoh (BPacket *packet);
diff -ru a/blib/breceiver.c b/blib/breceiver.c
--- a/blib/breceiver.c	2025-01-09 18:23:21.159070702 +0400
+++ b/blib/breceiver.c	2025-01-09 18:24:36.299648508 +0400
@@ -354,7 +354,7 @@
 
     case MAGIC_BLFRAME:
       {
-	gint size;
+	gsize size;
 
 	fake = b_packet_new (18, 8, 1, 1, &size);
 
Dealing with implicit declarations: autoreconf and #include "config.h"
in places where they were not included previously
diff -ru a/configure.in a/configure.in
--- a/configure.in	2025-01-09 18:10:29.297407580 +0400
+++ a/configure.in	2025-01-09 18:15:55.400575296 +0400
@@ -20,6 +20,8 @@
 BLIB_API_VERSION=$BLIB_MAJOR_VERSION.$BLIB_MINOR_VERSION
 BLIB_VERSION=$BLIB_MAJOR_VERSION.$BLIB_MINOR_VERSION.$BLIB_MICRO_VERSION
 
+AC_USE_SYSTEM_EXTENSIONS
+
 AC_SUBST(BLIB_MAJOR_VERSION)
 AC_SUBST(BLIB_MINOR_VERSION)
 AC_SUBST(BLIB_MICRO_VERSION)
diff -ru a/modules/bcountdown.c b/modules/bcountdown.c
--- a/modules/bcountdown.c	2025-01-09 18:23:21.161070691 +0400
+++ b/modules/bcountdown.c	2025-01-09 18:25:27.179362628 +0400
@@ -21,6 +21,8 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+#include "config.h"
+
 #include <stdlib.h>
 #include <string.h>
 #include <sys/time.h>
diff -ru a/modules/bdropout.c b/modules/bdropout.c
--- a/modules/bdropout.c	2025-01-09 18:23:21.161070691 +0400
+++ b/modules/bdropout.c	2025-01-09 18:25:53.499214744 +0400
@@ -18,6 +18,8 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+#include "config.h"
+
 #include <stdlib.h>
 
 #include <glib.h>
diff -ru a/modules/bpushline.c b/modules/bpushline.c
--- a/modules/bpushline.c	2025-01-09 18:23:21.161070691 +0400
+++ b/modules/bpushline.c	2025-01-09 18:23:30.867016155 +0400
@@ -18,6 +18,8 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+#include "config.h"
+
 #include <stdlib.h>
 
 #include <glib.h>
diff -ru a/modules/btetris.c b/modules/btetris.c
--- a/modules/btetris.c	2025-01-09 18:23:21.161070691 +0400
+++ b/modules/btetris.c	2025-01-09 18:25:36.835308374 +0400
@@ -18,6 +18,8 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+#include "config.h"
+
 #include <string.h>
 #include <stdlib.h>
 #include <unistd.h>