1 files changed, 26 insertions, 0 deletions
diff --git a/m4/secure_getenv.m4 b/m4/secure_getenv.m4
new file mode 100644
index 0000000..29e2f53
--- /dev/null
+++ b/m4/secure_getenv.m4
@@ -0,0 +1,26 @@
+# Look up an environment variable more securely.
+dnl Copyright 2013-2020 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.
+
+AC_DEFUN([gl_FUNC_SECURE_GETENV],
+[
+  dnl Persuade glibc <stdlib.h> to declare secure_getenv().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([secure_getenv])
+  if test $ac_cv_func_secure_getenv = no; then
+    HAVE_SECURE_GETENV=0
+  fi
+])
+
+# Prerequisites of lib/secure_getenv.c.
+AC_DEFUN([gl_PREREQ_SECURE_GETENV], [
+  AC_CHECK_FUNCS([__secure_getenv])
+  if test $ac_cv_func___secure_getenv = no; then
+    AC_CHECK_FUNCS([issetugid])
+  fi
+  AC_CHECK_FUNCS_ONCE([getuid geteuid getgid getegid])
+])