1 files changed, 46 insertions, 0 deletions
diff --git a/gnulib-m4/libdl.m4 b/gnulib-m4/libdl.m4
new file mode 100644
index 00000000..79d69063
--- /dev/null
+++ b/gnulib-m4/libdl.m4
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+# libdl.m4
+# serial 3
+dnl Copyright (C) 2024-2026 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl This file is offered as-is, without any warranty.
+
+dnl From Bruno Haible.
+
+dnl Set LIBDL to '-ldl' if it is needed to use the functions declared
+dnl in <dlfcn.h> (dlopen, dlsym, etc.), or to empty otherwise.
+AC_DEFUN([gl_LIBDL],
+[
+  dnl dlopen, dlsym are
+  dnl - in libc on glibc >= 2.34, musl libc, macOS, FreeBSD, NetBSD, OpenBSD,
+  dnl   AIX, Solaris, Cygwin, Haiku,
+  dnl - in a separate libdl on glibc < 2.34, uClibc, Android.
+  AC_CACHE_CHECK([for library needed for dlopen and dlsym],
+    [gl_cv_lib_dl],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <dlfcn.h>
+          ]],
+          [[return ! dlsym (RTLD_DEFAULT, "main");]])],
+       [gl_cv_lib_dl=none],
+       [gl_cv_lib_dl=maybe])
+     if test $gl_cv_lib_dl = maybe; then
+       saved_LIBS="$LIBS"
+       LIBS="$LIBS -ldl"
+       AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <dlfcn.h>
+            ]],
+            [[return ! dlsym (RTLD_DEFAULT, "main");]])],
+         [gl_cv_lib_dl='-ldl'],
+         [gl_cv_lib_dl=none])
+       LIBS="$saved_LIBS"
+     fi
+    ])
+  case "$gl_cv_lib_dl" in
+    none) LIBDL='' ;;
+    *)    LIBDL="$gl_cv_lib_dl" ;;
+  esac
+  AC_SUBST([LIBDL])
+])