fix executable creation for cross-installation

pkgs/racket-doc/scribblings/raco/exe-api.scrbl

@@ -473,9 +473,17 @@ A unit that imports nothing and exports @racket[compiler:embed^].}
 
 @defmodule[compiler/find-exe]
 
-@defproc[(find-exe [gracket? any/c #f]
-                   [variant (or/c 'cgc '3m) (system-type 'gc)])
+@defproc[(find-exe [#:cross? cross? any/c #f]
+                   [gracket? any/c #f]
+                   [variant (or/c 'cgc '3m) (if cross?
+                                                (cross-system-type 'gc)
+                                                (system-type 'gc))])
          path?]{
 
   Finds the path to the @exec{racket} or @exec{gracket} (when
-  @racket[gracket?] is true) executable.}
+  @racket[gracket?] is true) executable.
+
+  If @racket[cross?] is true, the executable is found for the target
+  platform in @seclink["cross-system"]{cross-installation mode}.
+
+  @history[#:changed "6.2.900.11" @elem{Added the @racket[#:cross?] argument.}]}

racket/collects/compiler/embed.rkt

@@ -1413,7 +1413,7 @@
                            cmdline)) . < . 80))
     (error 'create-embedding-executable "command line too long: ~e" cmdline))
   (check-collects-path 'create-embedding-executable collects-path collects-path-bytes)
-  (let ([exe (find-exe mred? variant)])
+  (let ([exe (find-exe #:cross? #t mred? variant)])
     (when verbose?
       (eprintf "Copying to ~s\n" dest))
     (let-values ([(dest-exe orig-exe osx?)

racket/collects/compiler/find-exe.rkt

@@ -1,9 +1,14 @@
 #lang racket/base
 (require setup/dirs
-         setup/variant)
+         setup/variant
+         setup/cross-system)
 (provide find-exe)
 
-(define (find-exe [mred? #f] [variant (system-type 'gc)])
+(define (find-exe #:cross? [cross? #f]
+                  [mred? #f]
+                  [variant (if cross?
+                               (cross-system-type 'gc)
+                               (system-type 'gc))])
   (let* ([base (if mred?
                    (find-lib-dir)
                    (find-console-bin-dir))]
@@ -15,7 +20,9 @@
                    variant))])
     (let ([exe (build-path
                 base
-                (case (system-type)
+                (case (if cross?
+                          (cross-system-type)
+                          (system-type))
                   [(macosx)
                    (cond
                      [(not mred?)