expander: fix module cache when current-load-relative-directory is #f

Corrects a problem with 4525c231a7.

racket/src/bc/src/startup.inc

@@ -38630,7 +38630,14 @@ static const char *startup_source =
 "(lambda(hash-code_0)"
 "(begin"
 "(if hash-code_0"
-"        (string->symbol (format \"~s\" (list hash-code_0 (path->directory-path (current-load-relative-directory)))))"
+"(string->symbol"
+"(format"
+"          \"~s\""
+"(list"
+" hash-code_0"
+"(path->directory-path"
+"(let-values(((or-part_0)(current-load-relative-directory)))"
+"(if or-part_0 or-part_0(current-directory)))))))"
 " #f))))"
 "(define-values"
 "(module-cache-set!)"

racket/src/cs/schemified/expander.scm

@@ -46072,7 +46072,9 @@
         "~s"
         (list
          hash-code_0
-         (path->directory-path (current-load-relative-directory)))))
+         (path->directory-path
+          (let ((or-part_0 (current-load-relative-directory)))
+            (if or-part_0 or-part_0 (current-directory)))))))
       #f)))
 (define module-cache-set!
   (lambda (key_0 proc_0)

racket/src/expander/eval/module-cache.rkt

@@ -29,7 +29,8 @@
        ;; Encode as a symbol so we can use an eq?-based hash table
        ;; (i.e., explot the low-level lock on the symbol table)
        (string->symbol (format "~s" (list hash-code (path->directory-path
-                                                     (current-load-relative-directory)))))))
+                                                     (or (current-load-relative-directory)
+                                                         (current-directory))))))))
 
 (define (module-cache-set! key proc)
   (hash-set! module-cache key (make-ephemeron key proc)))