* src/parse-gram.y (YYLLOC_DEFAULT, current_lhs_location): New.

(input): Don't try to initialize yylloc here, do it in the
scanner.
* src/scan-gram.l (YY_USER_INIT): Initialize yylloc.
* src/gram.h (rule_t): Change line and action_line into location
and action_location, of location_t type.
Adjust all dependencies.
* src/location.h, src/location.c (empty_location): New.
* src/reader.h, src/reader.c (grammar_start_symbol_set)
(grammar_symbol_append, grammar_rule_begin, grammar_rule_end)
(grammar_current_rule_symbol_append)
(grammar_current_rule_action_append): Expect a location as argument.
* src/reader.c (grammar_midrule_action): Adjust to attach an
action's location as dummy symbol location.
* src/symtab.h, src/symtab.c (startsymbol_location): New.
* tests/regression.at (Web2c Report, Rule Line Numbers): Adjust
the line numbers.

tests/regression.at

@@ -149,10 +149,10 @@ AT_CHECK([cat input.output], [],
 [[Grammar
 
   Number, Line, Rule
-    0   2 $axiom -> expr $
-    1   2 @1 -> /* empty */
+    0   5 $axiom -> expr $
+    1   5 @1 -> /* empty */
     2   2 expr -> 'a' @1 'b'
-    3  15 @2 -> /* empty */
+    3  18 @2 -> /* empty */
     4  15 expr -> @2 'c'
 
 
@@ -380,7 +380,7 @@ AT_CHECK([sed -n 's/  *$//;/^$/!p' input.output], 0,
     1   6 CONST_DEC_PART -> CONST_DEC_LIST
     2  10 CONST_DEC_LIST -> CONST_DEC
     3  12 CONST_DEC_LIST -> CONST_DEC_LIST CONST_DEC
-    4  15 @1 -> /* empty */
+    4  16 @1 -> /* empty */
     5  15 CONST_DEC -> @1 undef_id_tok '=' const_id_tok ';'
 Terminals, with rules where they appear
 $ (0) 0