fix redundant #defines

Removed from errsym.h (as built by errcode -d via the Makefile),
E__NONE, E__BASE, E__USERDEF, and E__USERMAX.  These symbols were
also defined in errtbl.h, which is NOW the place of the #define.

Update .gitigore with another temporary file.

value.c

@@ -37,6 +37,7 @@
 #include "nametype.h"
 #include "file.h"
 #include "config.h"
+#include "errtbl.h"
 
 
 #include "attribute.h"