simplify cross-compilation with a #:cross-target option

distro-build-doc/distro-build.scrbl

@@ -248,13 +248,6 @@ spaces, etc.):
   @item{@racket[#:pkgs (list _string* ...)] --- packages to install;
     defaults to the @tt{PKGS} makefile variable}
 
-  @item{@racket[#:racket _string-or-false] --- path to a native Racket
-    executable when using the client machine for cross-compilation; if
-    the value is @racket[#f], the the Racket executable generated for
-    the client machine is used to prepare the installer; a
-    non-@racket[#f] typically must be combined with
-    @racket[#:configure] arguments to set up cross-compilation}
-
   @item{@racket[#:dist-base-url _string] --- a URL that is used to
     construct a default for @racket[#:doc-search] and
     @racket[#:dist-catalogs], where the constructed values are
@@ -316,14 +309,33 @@ spaces, etc.):
     shown, for example, in the Virtual Box GUI); if provided, the
     virtual machine is started and stopped on the server as needed}
 
-  @item{@racket[#:platform <symbol>] --- @racket['unix],
+  @item{@racket[#:platform _symbol] --- @racket['unix],
     @racket['macosx], @racket['windows], or @racket['windows/bash]
     (which means @racket['windows] though an SSH server providing
-    @exec{bash}, such as Cygwin's); defaults to @racket[(system-type)]}
+    @exec{bash}, such as Cygwin's); the @racket[_symbol] names
+    the client machine's system, not the target for cross-compilation;
+    defaults to @racket[(system-type)]}
 
   @item{@racket[#:configure (list _string ...)] --- arguments to
     @exec{configure}}
 
+  @item{@racket[#:cross-target _string*] --- specifies a target for
+    cross-compilation, which adds @DFlag{host}@tt{=}@racket[_string*]
+    to the start of the list of @exec{configure} arguments; in
+    addition, if no @racket[#:racket] value is provided, a native
+    @exec{racket} executable for the client machine is created (by
+    using @exec{configure} with no arguments) and used for
+    cross-compilation in the same way as a @racket[#:racket] value}
+
+  @item{@racket[#:racket _string-or-false] --- an absolute path to a
+    native Racket executable to use for compilation, especially
+    cross-compilation; if the value is @racket[#f], then the Racket
+    executable generated for the client machine is used to prepare the
+    installer, or a client-native executable is generated
+    automatically if @racket[#:cross-target] is specified; a
+    non-@racket[#f] value for @racket[#:racket] is propagated to
+    @racket[#:configure] via @DFlag{enable-racket}}
+
   @item{@racket[#:bits _integer] --- @racket[32] or @racket[64];
     affects Visual Studio mode}
 

distro-build-server/config.rkt

@@ -114,6 +114,7 @@
   (case kw
     [(#:pkgs) (and (list? val) (andmap simple-string? val))]
     [(#:racket) (or (not val) (string? val))]
+    [(#:cross-target) (simple-string? val)]
     [(#:doc-search) (string? val)]
     [(#:dist-name) (string? val)]
     [(#:dist-base) (simple-string? val)]
@@ -190,7 +191,7 @@
   (and (string? s)
        ;; No spaces, quotes, or other things that could
        ;; break a command-line, path, or URL construction:
-       (regexp-match #rx"^[-a-zA-Z0-9.]*$" s)))
+       (regexp-match #rx"^[-a-zA-Z0-9._]*$" s)))
 
 (define (email? s)
   (and (string? s)

distro-build-server/drive-clients.rkt

@@ -300,6 +300,12 @@
                   (format "~a=~a" (car e) (cadr e)))))
      (list "/bin/sh" "-c" (apply ~a args))))
   (define j (or (get-opt c '#:j) 1))
+  (define cross-target (get-opt c '#:cross-target))
+  (define given-racket (and cross-target
+                            (get-opt c '#:racket)))
+  (define need-native-racket? (and cross-target
+                                   (not given-racket)))
+  (define built-native-racket "cross/racket/racket3m") ; relative to build directory
   (try-until-ready c host port user server-port 'unix (sh "echo hello"))
   (ssh-script
    host port user
@@ -313,11 +319,25 @@
    (and pull?
         (sh "cd " (q dir) " ; "
             "git pull"))
+   (and need-native-racket?
+        (sh "cd " (q dir) " ; "
+            "make native-for-cross"))
    (sh "cd " (q dir) " ; "
        "make -j " j " client"
        (client-args c server server-port 'unix readme)
        " JOB_OPTIONS=\"-j " j "\""
-       " CONFIGURE_ARGS_qq=" (qq (get-opt c '#:configure null) 'unix))))
+       (if need-native-racket?
+           (~a " PLAIN_RACKET=`pwd`/racket/src/build/" built-native-racket)
+           "")
+       " CONFIGURE_ARGS_qq=" (qq (append
+                                  (if cross-target
+                                      (list (~a "--enable-racket="
+                                                (or given-racket
+                                                    (~a "`pwd`/" built-native-racket)))
+                                            (~a "--host=" cross-target))
+                                      null)
+                                  (get-opt c '#:configure null))
+                                 'unix))))
 
 (define (windows-build c platform host port user server server-port repo clean? pull? readme)
   (define dir (get-path-opt c '#:dir "build\\plt" #:localhost (current-directory)))