Prefer signed to unsigned integers

This patch contains more fixes to prefer signed to unsigned
integer types, as modern tools like 'gcc -fsanitize=undefined'
can check for signed integer overflow but not unsigned overflow.
* NEWS: Document the API change.
* boostrap.conf (gnulib_modules): Add intprops.
* data/skeletons/glr.c: Include stddef.h and stdint.h,
since this skeleton can assume C99 or later.
(YYSIZEMAX): Now signed, and the minimum of SIZE_MAX and PTRDIFF_MAX.
(yybool) [!__cplusplus]: Now signed (which is how bool behaves).
(YYTRANSLATE): Avoid use of unsigned, and make the macro
safe even for values greater than UINT_MAX.
(yytnamerr, struct yyGLRState, struct yyGLRStateSet, struct yyGLRStack)
(yyaddDeferredAction, yyinitStateSet, yyinitGLRStack)
(yyexpandGLRStack, yymarkStackDeleted, yyremoveDeletes)
(yyglrShift, yyglrShiftDefer, yy_reduce_print, yydoAction)
(yyglrReduce, yysplitStack, yyreportTree, yycompressStack)
(yyprocessOneStack, yyreportSyntaxError, yyrecoverSyntaxError)
(yyparse, yy_yypstack, yypstack, yypdumpstack):
* tests/input.at (Torturing the Scanner):
Prefer ptrdiff_t to size_t.
* data/skeletons/c++.m4 (b4_yytranslate_define):
* src/AnnotationList.c (AnnotationList__computePredecessorAnnotations):
* src/AnnotationList.h (AnnotationIndex):
* src/InadequacyList.h (InadequacyListNodeCount):
* src/closure.c (closure_new):
* src/complain.c (error_message, complains, complain_indent)
(complain_args, duplicate_directive, duplicate_rule_directive):
* src/gram.c (nritems, ritem_print, grammar_dump):
* src/ielr.c (ielr_compute_ritem_sees_lookahead_set)
(ielr_item_has_lookahead, ielr_compute_annotation_lists)
(ielr_compute_lookaheads):
* src/location.c (columns, boundary_print, location_print):
* src/muscle-tab.c (muscle_percent_define_insert)
(muscle_percent_define_check_values):
* src/output.c (prepare_rules, prepare_actions):
* src/parse-gram.y (id, handle_require):
* src/reader.c (record_merge_function_type, packgram):
* src/reduce.c (nuseless_productions, nuseless_nonterminals)
(inaccessable_symbols):
* src/relation.c (relation_print):
* src/scan-code.l (variant, variant_table_size, variant_count)
(variant_add, get_at_spec, show_sub_message, show_sub_messages)
(parse_ref):
* src/scan-gram.l (<SC_ESCAPED_STRING,SC_ESCAPED_CHARACTER>)
(scan_integer, convert_ucn_to_byte, handle_syncline):
* src/scan-skel.l (at_complain):
* src/symtab.c (complain_symbol_redeclared)
(complain_semantic_type_redeclared, complain_class_redeclared)
(symbol_class_set, complain_user_token_number_redeclared):
* src/tables.c (conflict_tos, conflrow, conflict_table)
(conflict_list, save_row, pack_vector):
* tests/local.at (AT_YYLEX_DEFINE(c)):
Prefer signed to unsigned integer.
* data/skeletons/lalr1.cc (yy_lac_check_):
* tests/actions.at (_AT_CHECK_PRINTER_AND_DESTRUCTOR):
* tests/local.at (AT_YYLEX_DEFINE(c)):
Omit now-unnecessary casts.
* data/skeletons/location.cc (b4_location_define):
* doc/bison.texi (Mfcalc Lexer, C++ position, C++ location):
Prefer int to unsigned for line and column numbers.
Change example to abort explicitly on memory exhaustion,
and fix an off-by-one bug that led to undefined behavior.
* data/skeletons/stack.hh (stack::operator[]):
Also allow ptrdiff_t indexes.
(stack::pop, slice::slice, slice::operator[]):
Index arg is now ptrdiff_t, not int.
(stack::ssize): New method.
(slice::range_): Now ptrdiff_t, not int.
* data/skeletons/yacc.c (b4_state_num_type): Remove.
All uses replaced by b4_int_type.
(YY_CONVERT_INT_BEGIN, YY_CONVERT_INT_END): New macros.
(yylac, yyparse): Use them around conversions that -Wconversion
would give false alarms about. 	Omit unnecessary casts.
(yy_stack_print): Use int rather than unsigned, and omit
a cast that doesn’t seem to be needed here any more.
* examples/c++/variant.yy (yylex):
* examples/c++/variant-11.yy (yylex):
Omit no-longer-needed conversions to unsigned.
* src/InadequacyList.c (InadequacyList__new_conflict):
Don’t assume *node_count is unsigned.
* src/output.c (muscle_insert_unsigned_table):
Remove; no longer used.

data/skeletons/location.cc

@@ -65,8 +65,8 @@ m4_define([b4_location_define],
   public:]m4_ifdef([b4_location_constructors], [[
     /// Construct a position.
     explicit position (]b4_percent_define_get([[filename_type]])[* f = YY_NULLPTR,
-                       unsigned l = ]b4_location_initial_line[u,
-                       unsigned c = ]b4_location_initial_column[u)
+                       int l = ]b4_location_initial_line[u,
+                       int c = ]b4_location_initial_column[u)
       : filename (f)
       , line (l)
       , column (c)
@@ -75,8 +75,8 @@ m4_define([b4_location_define],
 ]])[
     /// Initialization.
     void initialize (]b4_percent_define_get([[filename_type]])[* fn = YY_NULLPTR,
-                     unsigned l = ]b4_location_initial_line[u,
-                     unsigned c = ]b4_location_initial_column[u)
+                     int l = ]b4_location_initial_line[u,
+                     int c = ]b4_location_initial_column[u)
     {
       filename = fn;
       line = l;
@@ -105,16 +105,15 @@ m4_define([b4_location_define],
     /// File name to which this position refers.
     ]b4_percent_define_get([[filename_type]])[* filename;
     /// Current line number.
-    unsigned line;
+    int line;
     /// Current column number.
-    unsigned column;
+    int column;
 
   private:
     /// Compute max (min, lhs+rhs).
-    static unsigned add_ (unsigned lhs, int rhs, int min)
+    static int add_ (int lhs, int rhs, int min)
     {
-      return static_cast<unsigned> (std::max (min,
-                                              static_cast<int> (lhs) + rhs));
+      return std::max (min, lhs + rhs);
     }
   };
 
@@ -197,8 +196,8 @@ m4_define([b4_location_define],
 
     /// Construct a 0-width location in \a f, \a l, \a c.
     explicit location (]b4_percent_define_get([[filename_type]])[* f,
-                       unsigned l = ]b4_location_initial_line[u,
-                       unsigned c = ]b4_location_initial_column[u)
+                       int l = ]b4_location_initial_line[u,
+                       int c = ]b4_location_initial_column[u)
       : begin (f, l, c)
       , end (f, l, c)
     {}
@@ -206,8 +205,8 @@ m4_define([b4_location_define],
 ])[
     /// Initialization.
     void initialize (]b4_percent_define_get([[filename_type]])[* f = YY_NULLPTR,
-                     unsigned l = ]b4_location_initial_line[u,
-                     unsigned c = ]b4_location_initial_column[u)
+                     int l = ]b4_location_initial_line[u,
+                     int c = ]b4_location_initial_column[u)
     {
       begin.initialize (f, l, c);
       end = begin;
@@ -305,7 +304,7 @@ m4_define([b4_location_define],
   std::basic_ostream<YYChar>&
   operator<< (std::basic_ostream<YYChar>& ostr, const location& loc)
   {
-    unsigned end_col = 0 < loc.end.column ? loc.end.column - 1 : 0;
+    int end_col = 0 < loc.end.column ? loc.end.column - 1 : 0;
     ostr << loc.begin;
     if (loc.end.filename
         && (!loc.begin.filename