Updated sulogin.c to pull in crypt.h as it is a new, undocumented

dependency on Fedora 28.
Confirmed we can still build on other/older platforms.

src/Makefile

@@ -10,7 +10,7 @@
 
 CPPFLAGS =
 CFLAGS	?= -ansi -O2 -fomit-frame-pointer -fstack-protector 
-override CFLAGS += -W -Wall -Wunreachable-code -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -D_XOPEN_SOURCE -D_GNU_SOURCE
+override CFLAGS += -W -Wall -Wunreachable-code -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -D_XOPEN_SOURCE -D_GNU_SOURCE 
 override CFLAGS += $(shell getconf LFS_CFLAGS)
 STATIC	=
 MANDB	:= s@^\('\\\\\"\)[^\*-]*-\*- coding: [^[:blank:]]\+ -\*-@\1@

src/sulogin.c

@@ -39,6 +39,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <crypt.h>    /* added to make this compile on Fedora 28 */
 #include <fcntl.h>
 #include <signal.h>
 #include <pwd.h>