Do not worry about whether locale.h is includable

* src/emacs.c, src/lread.c, src/sysdep.c: Remove preconditions
from including locale.h.  It was standardized in C89, is universal
now, and some code already assumes it.

src/emacs.c

@@ -23,6 +23,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 #include <errno.h>
 #include <fcntl.h>
+#include <locale.h>
 #include <stdlib.h>
 
 #include <sys/file.h>
@@ -132,10 +133,6 @@ extern char etext;
 # endif
 #endif
 
-#ifdef HAVE_SETLOCALE
-#include <locale.h>
-#endif
-
 #if HAVE_WCHAR_H
 # include <wchar.h>
 #endif

src/lread.c

@@ -28,6 +28,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include <sys/stat.h>
 #include <sys/file.h>
 #include <errno.h>
+#include <locale.h>
 #include <math.h>
 #include <stat-time.h>
 #include "lisp.h"
@@ -55,11 +56,6 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #endif
 
 #include <unistd.h>
-
-#ifdef HAVE_SETLOCALE
-#include <locale.h>
-#endif /* HAVE_SETLOCALE */
-
 #include <fcntl.h>
 
 #if !defined HAVE_ANDROID || defined ANDROID_STUBIFY	\

src/sysdep.c

@@ -4551,9 +4551,7 @@ does the same thing as `current-time'.  */)
 # include <wchar.h>
 # include <wctype.h>
 
-# if defined HAVE_NEWLOCALE || defined HAVE_SETLOCALE
-#  include <locale.h>
-# endif
+# include <locale.h>
 # ifndef LC_COLLATE
 #  define LC_COLLATE 0
 # endif