diff --git a/meson.build b/meson.build
index 8d5ee4f579..56b841ed35 100644
--- a/meson.build
+++ b/meson.build
@@ -1691,14 +1691,13 @@ system_includes = [
         ),
 ]
 
-if get_option('libc') == 'musl'
-        system_include_args = [
-                '-isystem', meson.project_build_root()  / 'src/include/musl',
-                '-isystem', meson.project_source_root() / 'src/include/musl',
-        ] + system_include_args
+libc_include_dir = 'src/include' / get_option('libc')
+system_include_args = [
+        '-isystem', meson.project_build_root()  / libc_include_dir,
+        '-isystem', meson.project_source_root() / libc_include_dir,
+] + system_include_args
 
-        system_includes += include_directories('src/include/musl', is_system : true)
-endif
+system_includes += include_directories(libc_include_dir, is_system : true)
 
 basic_includes = [
         include_directories(
diff --git a/src/include/glibc/stdio.h b/src/include/glibc/stdio.h
new file mode 100644
index 0000000000..7e45cb3ba2
--- /dev/null
+++ b/src/include/glibc/stdio.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/* Force glibc's stdio.h to route sscanf/fscanf to the old __isoc99_* siblings (GLIBC_2.7) rather
+ * than the newer __isoc23_* ones (GLIBC_2.38). The only behavioural difference is "0b" prefix
+ * support in %i conversions, which we don't use. We include features.h first so the macro is set
+ * to its normal value, then override it before stdio.h's body evaluates __GLIBC_USE(C23_STRTOL).
+ *
+ * The macro was named __GLIBC_USE_C2X_STRTOL on glibc 2.38–2.39 and renamed to the C23 spelling
+ * in glibc 2.40; clear both so this override works across that range. */
+
+#include <features.h>
+#undef __GLIBC_USE_C2X_STRTOL
+#define __GLIBC_USE_C2X_STRTOL 0
+#undef __GLIBC_USE_C23_STRTOL
+#define __GLIBC_USE_C23_STRTOL 0
+
+#include_next <stdio.h>      /* IWYU pragma: export */
diff --git a/src/include/glibc/stdlib.h b/src/include/glibc/stdlib.h
new file mode 100644
index 0000000000..a3ad2a3b5a
--- /dev/null
+++ b/src/include/glibc/stdlib.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/* Force glibc's stdlib.h to leave strtol/strtoul/strtoll/strtoull as their original GLIBC_2.2.5
+ * symbols rather than redirect to __isoc23_* (GLIBC_2.38). The only behavioural difference is
+ * "0b" prefix support in base 0/2 parsing, which we don't use.
+ *
+ * The macro was named __GLIBC_USE_C2X_STRTOL on glibc 2.38–2.39 and renamed to the C23 spelling
+ * in glibc 2.40; clear both so this override works across that range. */
+
+#include <features.h>
+#undef __GLIBC_USE_C2X_STRTOL
+#define __GLIBC_USE_C2X_STRTOL 0
+#undef __GLIBC_USE_C23_STRTOL
+#define __GLIBC_USE_C23_STRTOL 0
+
+#include_next <stdlib.h>     /* IWYU pragma: export */