[USE_CRT_DLL]: Remove unnecessary extern, which screws

up dllimport attributes.

src/editfns.c

@@ -49,7 +49,10 @@ Boston, MA 02111-1307, USA.  */
 #define NULL 0
 #endif
 
+#ifndef USE_CRT_DLL
 extern char **environ;
+#endif
+
 extern Lisp_Object make_time P_ ((time_t));
 extern size_t emacs_strftimeu P_ ((char *, size_t, const char *,
 				   const struct tm *, int));

src/fileio.c

@@ -65,8 +65,10 @@ Boston, MA 02111-1307, USA.  */
 #include <errno.h>
 
 #ifndef vax11c
+#ifndef USE_CRT_DLL
 extern int errno;
 #endif
+#endif
 
 #ifdef APOLLO
 #include <sys/time.h>

src/floatfns.c

@@ -107,8 +107,10 @@ extern double logb ();
 #ifdef FLOAT_CHECK_ERRNO
 # include <errno.h>
 
+#ifndef USE_CRT_DLL
 extern int errno;
 #endif
+#endif
 
 /* Avoid traps on VMS from sinh and cosh.
    All the other functions set errno instead.  */