Make clojure.spec.alpha load and run

Four general gaps, shaken out by loading clojure.spec.alpha:

- Special forms were shadowable by a same-named macro. analyze-list
  macroexpanded before checking special forms, so a ns that redefs def/and/or
  (spec excludes them via :refer-clojure :exclude) made a bare def resolve to
  the macro instead of the special form, breaking every defn after. Now a head
  in the special-form set is never macroexpanded, matching the reference
  macroexpand1 isSpecial check.

- reify dropped all but the last arity of a multi-arity protocol method (spec
  reifies (specize* [s]) and (specize* [s _])). The macro keyed methods by name
  and overwrote; now it groups arities into one multi-arity fn.

- reify instances did not implement IObj: with-meta threw and (instance?
  clojure.lang.IObj r) was false. Every Clojure reify carries metadata. with-meta
  now copies the reify to a fresh identity (shared method table) and keys its
  meta; instance? IObj/IMeta is true for any reify. This was the registry bug —
  spec's with-name returned nil for specs, so get-spec missed.

- (set! (. Class field) val) was rejected. spec toggles
  clojure.lang.RT/checkSpecAsserts this way; the analyzer now lowers it to a
  jolt.host/set-static-field! call over a mutable-statics table, and a plain
  Class/field read consults that table.

Also: .name/.getName on a Namespace and .ns/.sym on a Var (spec's ns-qualify /
->sym). analyzer + reify are seed sources (re-minted). spec.alpha now does
valid?/conform/cat/keys/explain-str/check-asserts. tick.alpha.interval-test still
needs time-literals data readers (separate).

host/chez/host-static.ss

@@ -90,13 +90,35 @@
     ((string=? method "isInfinite") (and (flonum? n) (infinite? n)))
     (else (error #f (string-append "No method " method " for number")))))
 
+;; Mutable static fields: "Class" -> (member -> 1-vector cell). A library that
+;; writes a static field — clojure.spec.alpha's (set! (. clojure.lang.RT
+;; checkSpecAsserts) flag) — lands here; the analyzer lowers the set! to a
+;; set-static-field! call and a plain Class/member read consults the cell first.
+(define mutable-statics-tbl (make-hashtable string-hash string=?))
+(define (mutable-static-cell class member create?)
+  (let ((h (or (hashtable-ref mutable-statics-tbl class #f)
+               (and create? (let ((nh (make-hashtable string-hash string=?)))
+                              (hashtable-set! mutable-statics-tbl class nh) nh)))))
+    (and h (or (hashtable-ref h member #f)
+               (and create? (let ((c (vector jolt-nil))) (hashtable-set! h member c) c))))))
+(def-var! "jolt.host" "set-static-field!"
+  (lambda (class member val)
+    (vector-set! (mutable-static-cell class member #t) 0 val)
+    val))
+;; clojure.lang.RT.checkSpecAsserts — a JVM-internal flag clojure.spec.alpha reads
+;; and writes; default false. Pre-seed the cell so a read before any write works.
+(vector-set! (mutable-static-cell "clojure.lang.RT" "checkSpecAsserts" #t) 0 #f)
+
 ;; ---- emit entry points ------------------------------------------------------
 (define (host-static-ref class member)
-  (let ((h (lookup-class class-statics-tbl class)))
-    (if h
-        (let ((v (hashtable-ref h member #f)))
-          (if v v (error #f (string-append "No static " class "/" member))))
-        (error #f (string-append "Unknown class " class)))))
+  (let ((cell (mutable-static-cell class member #f)))
+    (if cell
+        (vector-ref cell 0)
+        (let ((h (lookup-class class-statics-tbl class)))
+          (if h
+              (let ((v (hashtable-ref h member #f)))
+                (if v v (error #f (string-append "No static " class "/" member))))
+              (error #f (string-append "Unknown class " class)))))))
 
 (define (host-static-call class member . args)
   (apply (host-static-ref class member) args))