add racket/private/primitive-table

Like `racket/private/check`, this module simplifies a "racket7"
bootstrap.

racket/collects/racket/private/primitive-table.rkt

@@ -0,0 +1,23 @@
+#lang racket/base
+(require (only-in '#%linklet primitive-table))
+
+;; By using only `primitive-table` directly, that's the only function
+;; needed for bootstrapping situations (that might even replace the
+;; linklet implementation otherwise).
+
+(provide import-from-primitive-table)
+
+(define-syntax import-from-primitive-table
+  (syntax-rules ()
+    [(_ (table-name ...) [id import-id])
+     ;; Linklet-flattening tools can recognize this specific pattern
+     ;; to substitute a static reference for a dynamic lookup
+     (define import-id (hash-ref (or (primitive-table 'table-name) ...) 'id #f))]
+    [(_ table-name [id import-id])
+     (import-from-primitive-table (table-name) [id import-id])]
+    [(_ tables id)
+     (import-from-primitive-table tables [id id])]
+    [(_ tables bind ...)
+     (begin
+       (import-from-primitive-table tables bind)
+       ...)]))