[9front] [PATCH] cc: support const and restrict inside array declarations

[mia soweli <inbox@tachibana-labs.org>]

this allows c23 style array declarations (see c23 draft section 6.7.6),
with type qualifiers inside the brackets.
for example:

	const int list[restrict 4];
	int list[const 4];
	int list[const restrict 4];
	int list[volatile 4];
	int list[noret 4]; /* we may not want to allow this */

they are ignored as with other uses of const, restrict, and volatile.
it does not allow

	int list[static 4];

which is also allowed in c23.

diff 090af6255bebf0129c891116b53b31808fe49dc7 uncommitted
--- a/sys/src/cmd/cc/cc.y
+++ b/sys/src/cmd/cc/cc.y
@@ -142,9 +142,9 @@
 	{
 		$$ = new(OFUNC, $1, $3);
 	}
-|	xdecor2 '[' zexpr ']'
+|	xdecor2 '[' zgnlist zexpr ']'
 	{
-		$$ = new(OARRAY, $1, $3);
+		$$ = new(OARRAY, $1, $4);
 	}
 
 /*
@@ -273,9 +273,9 @@
 	{
 		$$ = new(OFUNC, $1, $3);
 	}
-|	abdecor2 '[' zexpr ']'
+|	abdecor2 '[' zgnlist zexpr ']'
 	{
-		$$ = new(OARRAY, $1, $3);
+		$$ = new(OARRAY, $1, $4);
 	}
 
 abdecor3:
@@ -283,9 +283,9 @@
 	{
 		$$ = new(OFUNC, (Z), Z);
 	}
-|	'[' zexpr ']'
+|	'[' zgnlist zexpr ']'
 	{
-		$$ = new(OARRAY, (Z), $2);
+		$$ = new(OARRAY, (Z), $3);
 	}
 |	'(' abdecor1 ')'
 	{