Get Bison to build again when configured with --enable-gcc-warnings.

* src/location.c, src/location.h, src/main.c, src/scan-code.l: Add some
missing #include's.
* src/scan-code.l (handle_action_dollar, handle_action_at): Rename
loc argument as it shadows a global.
* src/scan-gram.l: Remove stray comma that prevents boundary_set
invocation.

* src/.cvsignore: Add scan-code.c.

src/main.c

@@ -43,6 +43,7 @@
 #include "print_graph.h"
 #include "reader.h"
 #include "reduce.h"
+#include "scan-gram.h"
 #include "symtab.h"
 #include "tables.h"
 #include "uniqstr.h"