diff --git a/xdm/session.c b/xdm/session.c
index 4f71d713d6b5fe6563e8de1eb0e6a9d1ec8d48ab..4ab98c1c5999a39bbc207ecaa1c975855fc0793a 100644
--- a/xdm/session.c
+++ b/xdm/session.c
@@ -137,6 +137,9 @@ extern	void	endspent(void);
 #if defined(CSRG_BASED) || defined(__GLIBC__)
 # include <pwd.h>
 # include <unistd.h>
+# if defined(__GLIBC__) && !defined(_XOPEN_CRYPT)
+# include <crypt.h>
+# endif
 #else
 extern	struct passwd	*getpwnam(GETPWNAM_ARGS);
 # ifdef linux