Fixes compilation with -nls useflag on FreeBSD (and probably others).

See http://bugs.gentoo.org/253777.

--- grep-2.5.3.orig/lib/error.c
+++ grep-2.5.3/lib/error.c
@@ -26,8 +26,8 @@
 #endif
 
 #include <stdio.h>
-#if HAVE_LIBINTL_H
-# include <libintl.h>
+#if defined(HAVE_LIBINTL_H) && defined(ENABLE_NLS)
+#  include <libintl.h>
 #endif
 
 #if HAVE_VPRINTF || HAVE_DOPRNT || _LIBC
--- grep-2.5.3.orig/lib/getopt.c
+++ grep-2.5.3/lib/getopt.c
@@ -77,7 +77,7 @@
 #ifndef _
 /* This is for other GNU distributions with internationalized messages.
    When compiling libc, the _ macro is predefined.  */
-# ifdef HAVE_LIBINTL_H
+# if defined(HAVE_LIBINTL_H) && defined(ENABLE_NLS)
 #  include <libintl.h>
 #  define _(msgid)	gettext (msgid)
 # else
--- grep-2.5.3.orig/lib/obstack.c
+++ grep-2.5.3/lib/obstack.c
@@ -451,7 +451,7 @@
 
 /* Define the error handler.  */
 #ifndef _
-# ifdef HAVE_LIBINTL_H
+# if defined(HAVE_LIBINTL_H) && defined(ENABLE_NLS)
 #  include <libintl.h>
 #  ifndef _
 #   define _(Str) gettext (Str)
--- grep-2.5.3.orig/lib/regex.c
+++ grep-2.5.3/lib/regex.c
@@ -116,7 +116,7 @@
 #endif
 
 /* This is for other GNU distributions with internationalized messages.  */
-#if HAVE_LIBINTL_H || defined _LIBC
+#if ENABLE_NLS && (HAVE_LIBINTL_H || defined _LIBC)
 # include <libintl.h>
 # ifdef _LIBC
 #  undef gettext