Fix static multicall bootstrap discovery

ober

7a3b35aaee9c013bdd62cdc2805fd864714248ef

diff --git a/lib/std/native-loader.ss b/lib/std/native-loader.ss
index ae5d33e..9420a0e 100644
--- a/lib/std/native-loader.ss
+++ b/lib/std/native-loader.ss
@@ -91,7 +91,8 @@
       (bootstrap-symbols-available?)))
 
   (define system-libc-loaded
-    (or (try-load-system-object #f)
+    (or (bootstrap-symbols-available?)
+        (try-load-system-object #f)
         (let loop ([paths system-libc-paths])
           (and (pair? paths)
                (or (try-load-system-object (car paths))
diff --git a/support/build-jerboa-multicall.ss b/support/build-jerboa-multicall.ss
index 8d27ab6..e6fdb8c 100644
--- a/support/build-jerboa-multicall.ss
+++ b/support/build-jerboa-multicall.ss
@@ -1386,7 +1386,7 @@
 (define binary-wpo?
   (env-enabled? "JERBOA_BINARY_WPO" #f))
 
-(define csv-dir (or (getenv "CHEZ_DIR")
+(define csv-dir (or (env "CHEZ_DIR" #f)
                     (find-csv-dir (format "~a/lib" (if cross? cross-prefix (format "~a/.chez" repo)))
                                   machine)))
 (unless csv-dir (error 'build-multicall "no Chez csv dir for" machine