configure: check whether fgetpwent_r is available before marking xprefix_getpwnam_r as reentrant

configure.ac

@@ -678,6 +678,8 @@ if test "$with_skey" = "yes"; then
 	]])],[AC_DEFINE(SKEY_BSD_STYLE, 1, [Define to support newer BSD S/Key API])],[])
 fi
 
+AC_CHECK_FUNC(fgetpwent_r, [AC_DEFINE(HAVE_FGETPWENT_R, 1, [Defined to 1 if you have the declaration of 'fgetpwent_r'])])
+
 AC_DEFINE_UNQUOTED(SHELL, ["$SHELL"], [The default shell.])
 
 AM_GNU_GETTEXT_VERSION([0.19])

lib/prototypes.h

@@ -324,8 +324,10 @@ extern struct group *prefix_getgrnam(const char *name);
 extern struct group *prefix_getgrgid(gid_t gid);
 extern struct passwd *prefix_getpwuid(uid_t uid);
 extern struct passwd *prefix_getpwnam(const char* name);
+#if HAVE_FGETPWENT_R
 extern int prefix_getpwnam_r(const char* name, struct passwd* pwd,
                              char* buf, size_t buflen, struct passwd** result);
+#endif
 extern struct spwd *prefix_getspnam(const char* name);
 extern struct group *prefix_getgr_nam_gid(const char *grname);
 extern void prefix_setpwent(void);

libmisc/prefix_flag.c

@@ -238,6 +238,7 @@ extern struct passwd *prefix_getpwnam(const char* name)
 		return getpwnam(name);
 	}
 }
+#if HAVE_FGETPWENT_R
 extern int prefix_getpwnam_r(const char* name, struct passwd* pwd,
                              char* buf, size_t buflen, struct passwd** result)
 {
@@ -259,6 +260,7 @@ extern int prefix_getpwnam_r(const char* name, struct passwd* pwd,
 		return getpwnam_r(name, pwd, buf, buflen, result);
 	}
 }
+#endif
 extern struct spwd *prefix_getspnam(const char* name)
 {
 	if (spw_db_file) {

libmisc/xprefix_getpwnam.c

@@ -35,7 +35,7 @@
 #define ARG_TYPE	const char *
 #define ARG_NAME	name
 #define DUP_FUNCTION	__pw_dup
-#define HAVE_FUNCTION_R 1
+#define HAVE_FUNCTION_R HAVE_FGETPWENT_R
 
 #include "xgetXXbyYY.c"