This patch is from the upstream repo, from between the tags libcap-2.75
and libcap-2.76, and can be removed after the update to 2.76.

From 04b285680bfb45117af685eabf1675917118bdb5 Mon Sep 17 00:00:00 2001
Message-ID: <04b285680bfb45117af685eabf1675917118bdb5.1764517342.git.efraim@flashner.co.il>
From: "Andrew G. Morgan" <morgan@kernel.org>
Date: Sat, 22 Mar 2025 09:49:50 -0700
Subject: [PATCH] Glibc needs a constant to be defined for puts() to work.

See https://bugzilla.kernel.org/show_bug.cgi?id=219880

Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
---
 libcap/execable.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/libcap/execable.h b/libcap/execable.h
index 89e61a3..a68ea24 100644
--- a/libcap/execable.h
+++ b/libcap/execable.h
@@ -23,6 +23,17 @@
 #endif
 #define __EXECABLE_H
 
+#ifdef __GLIBC__
+/*
+ * https://bugzilla.kernel.org/show_bug.cgi?id=219880 So far as I can
+ * tell this value is some legacy magic meaning, but is a detail no
+ * longer important to glibc. Only the existence of this constant in
+ * the linkage is needed.
+ */
+extern const int _IO_stdin_used;
+const int _IO_stdin_used __attribute__((weak)) = 131073;
+#endif /* def __GLIBC__ */
+
 const char __execable_dl_loader[] __attribute((section(".interp"))) =
     SHARED_LOADER ;
 
-- 
Efraim Flashner   <efraim@flashner.co.il>   אפרים פלשנר
GPG key = A28B F40C 3E55 1372 662D  14F7 41AA E7DC CA3D 8351
Confidentiality cannot be guaranteed on emails sent or received unencrypted