Define HAVE_STRUCT_UTMP_UT_HOST in order for the REMOTEHOST environment

variable to show up correctly.

Note: This is really a bug with the stock tcsh configure.in script not
including <sys/types.h> before <utmp.h>. But, since config.h is maintained
separate from the contrib sources, this is the correct fix.

Noticed by: ache

bin/csh/config.h

@@ -99,7 +99,7 @@
 #define HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY 1
 
 /* Define to 1 if `ut_host' is member of `struct utmp'. */
-/* #undef HAVE_STRUCT_UTMP_UT_HOST */
+#define HAVE_STRUCT_UTMP_UT_HOST 1
 
 /* Define to 1 if `ut_tv' is member of `struct utmp'. */
 /* #undef HAVE_STRUCT_UTMP_UT_TV */