diff --git a/cf/check-getpwnam_r-posix.m4 b/cf/check-getpwnam_r-posix.m4
new file mode 100644
index 000000000..106c2968f
--- /dev/null
+++ b/cf/check-getpwnam_r-posix.m4
@@ -0,0 +1,24 @@
+dnl $Id
+dnl
+dnl check for getpwnam_r, and if it's posix or not
+
+AC_DEFUN(AC_CHECK_GETPWNAM_R_POSIX,
+AC_FIND_FUNC_NO_LIBS(getpwnam_r,c_r)
+if test "$ac_cv_func_getpwnam_r" = yes; then
+	AC_CACHE_CHECK(if getpwnam_r is posix,ac_cv_func_getpwnam_r_posix,
+	ac_libs="$LIBS"
+	LIBS="$LIBS $LIB_getpwnam_r"
+	AC_TRY_RUN([
+#include <pwd.h>
+int main()
+{
+	struct passwd pw, *pwd;
+	return getpwnam_r("", &pw, NULL, 0, &pwd) < 0;
+}
+],ac_cv_func_getpwnam_r_posix=yes,ac_cv_func_getpwnam_r_posix=no,:)
+LIBS="$ac_libs")
+if test "$ac_cv_func_getpwnam_r_posix" = yes; then
+	AC_DEFINE(POSIX_GETPWNAM_R, 1, [Define if getpwnam_r has POSIX flavour.])
+fi
+fi
+)
\ No newline at end of file