Allow bit-fields in unions.

All versions of standard C allow this, but ORCA/C previously did not.

Parser.pas

@@ -2795,10 +2795,12 @@ var
                   fl := variable;
                   end; {if}
                end; {if}
+            if kind = unionType then begin
+               disp := 0;
+               bitdisp := 0;
+               end; {if}
             if token.kind = colonch then {handle a bit field}
                begin
-               if kind = unionType then
-                  Error(56);
                NextToken;
                Expression(arrayExpression,[commach,semicolonch]);
                if (expressionValue >= maxBitField) or (expressionValue < 0) then
@@ -2823,6 +2825,9 @@ var
                else
                   tPtr := typeSpec;
                bitdisp := bitdisp+long(expressionValue).lsw;
+               if kind = unionType then
+                  if ((bitDisp+7) div 8) > maxDisp then
+                     maxDisp := ((bitDisp+7) div 8);
                if (tPtr^.kind <> scalarType)
                   or not (tPtr^.baseType in
                      [cgByte,cgUByte,cgWord,cgUWord,cgLong,cgULong])
@@ -2836,9 +2841,7 @@ var
                if bitdisp <> 0 then begin
                   disp := disp+((bitDisp+7) div 8);
                   bitdisp := 0;
-                  end {if}
-               else if kind = unionType then
-                  disp := 0;
+                  end; {if}
                variable^.disp := disp;
                variable^.bitdisp := bitdisp;
                variable^.bitsize := 0;

Scanner.pas

@@ -627,7 +627,7 @@ if list or (numErr <> 0) then begin
          53: msg := @'the structure or union has already been defined';
          54: msg := @'bit fields must be less than 32 bits wide';
          55: msg := @'a value cannot be zero bits wide';
-         56: msg := @'bit fields in unions are not supported by ORCA/C';
+        {56: msg := @'bit fields in unions are not supported by ORCA/C';}
          57: msg := @'compiler error';
          58: msg := @'implementation restriction: too many local labels';
          59: msg := @'file name expected';

cc.notes

@@ -206,6 +206,10 @@ p. 277
 
 The type "long double" now specifies a number in the SANE extended format.
 
+p. 286
+
+Unions may now contain bit fields.
+
 p. 289
 
 Unions can be initialized by a brace-enclosed expression giving the initializer value for the first element of the union, or by an expression of the appropriate union type.  The non-standard construct of initializing the first element of a union with a non-brace-enclosed initializer is no longer supported.  The supported alternative is simply to enclose the initializer in braces, e.g.
@@ -1370,6 +1374,8 @@ int foo(int[42]);
 
 167. If an array with automatic storage duration was initialized from a string literal containing an embedded null byte (e.g. char s[] = "a\0b"), characters after the null byte would not be properly initialized.
 
+168. Unions may now contain bit-fields, as specified in the C standards.
+
 -- Bugs from C 2.1.0 that have been fixed -----------------------------------
 
 1.  In some situations, fread() reread the first 1K or so of the file.