cs: sync with Chez Scheme update

The Chez Scheme change avoids a leak while collecting in counting
mode, which is used by Racket's memory-accounting mode.

Also, add a small repair for 4256214981.

pkgs/base/info.rkt

@@ -12,7 +12,7 @@
 
 (define collection 'multi)
 
-(define version "7.7.0.1")
+(define version "7.7.0.2")
 
 (define deps `("racket-lib"
                ["racket" #:version ,version]))

racket/src/cs/compile-file.ss

@@ -2,7 +2,7 @@
 ;; Check to make we're using a build of Chez Scheme
 ;; that has all the features we need.
 (define-values (need-maj need-min need-sub need-dev)
-  (values 9 5 3 25))
+  (values 9 5 3 26))
 
 (unless (guard (x [else #f]) (eval 'scheme-fork-version-number))
   (error 'compile-file

racket/src/cs/rumble/memory.ss

@@ -115,7 +115,7 @@
           ;; that value may include underused pages that have locked objects.
           ;; Using just `post-allocated` is too small, because it may force an
           ;; immediate major GC too soon. Split the difference.
-          (set! trigger-major-gc-allocated (* GC-TRIGGER-FACTOR post-allocated))
+          (set! trigger-major-gc-allocated (* GC-TRIGGER-FACTOR (- post-allocated (bytes-finalized))))
           (set! trigger-major-gc-allocated+overhead (* GC-TRIGGER-FACTOR post-allocated+overhead)))
         (update-eq-hash-code-table-size!)
         (update-struct-procs-table-sizes!)

racket/src/racket/src/schvers.h

@@ -16,7 +16,7 @@
 #define MZSCHEME_VERSION_X 7
 #define MZSCHEME_VERSION_Y 7
 #define MZSCHEME_VERSION_Z 0
-#define MZSCHEME_VERSION_W 1
+#define MZSCHEME_VERSION_W 2
 
 /* A level of indirection makes `#` work as needed: */
 #define AS_a_STR_HELPER(x) #x

racket/src/thread/custodian.rkt

@@ -570,6 +570,7 @@
                        (set-custodian-memory-limits! c new-limits)
                        (when (and (pair? old-limits)
                                   (or (null? new-limits)
+                                      (not (custodian-gc-roots c))
                                       (zero? (hash-count (custodian-gc-roots c)))))
                          (hash-remove! custodians-with-limits c))
                        (or any-limits? (pair? new-limits))))