expander: fix make for generating BC source

Also, update "README.txt" to explain both CS and BC setup.

racket/src/cs/schemified/expander.scm

@@ -125,72 +125,72 @@
 (define kw2194 (string->keyword "set-hash!"))
 (define hash2936
   (hasheq
-   kw2755
-   '25
-   kw2641
-   '4
-   kw2129
-   '16
-   kw2821
-   '11
-   kw2607
-   '3
-   kw3245
-   '13
-   kw2582
-   '13
-   kw2099
-   '5
-   kw2201
-   '20
-   kw2226
-   '6
-   kw2535
-   '17
    kw3163
    '9
-   kw2600
-   '23
-   kw2333
-   '14
-   kw2626
-   '8
-   kw2603
-   '1
-   kw2931
-   '15
-   kw2802
-   '12
-   kw2525
-   '10
-   kw2967
-   '12
-   kw2677
-   '26
-   kw2804
-   '24
-   kw2762
-   '27
-   kw2473
-   '14
-   kw1932
-   '2
-   kw2496
-   '7
-   kw2169
-   '21
    kw2707
    '22
+   kw2600
+   '23
    kw2241
    '18
+   kw2333
+   '14
    kw2645
    '19
+   kw2626
+   '8
    kw3357
    '14
+   kw2603
+   '1
    kw2796
    '13
+   kw2755
+   '25
+   kw2931
+   '15
    kw2897
-   '28))
+   '28
+   kw2641
+   '4
+   kw2802
+   '12
+   kw2129
+   '16
+   kw2525
+   '10
+   kw2821
+   '11
+   kw2967
+   '12
+   kw2607
+   '3
+   kw2677
+   '26
+   kw3245
+   '13
+   kw2804
+   '24
+   kw2582
+   '13
+   kw2762
+   '27
+   kw2099
+   '5
+   kw2473
+   '14
+   kw2201
+   '20
+   kw1932
+   '2
+   kw2226
+   '6
+   kw2496
+   '7
+   kw2535
+   '17
+   kw2169
+   '21))
 (define kw2162 (string->keyword "not-recorded"))
 (define hash2430
   (hasheq

racket/src/expander/README.txt

@@ -1,4 +1,4 @@
-This package contains the implementation of Racket's front-end: macro
+This package contains the implementation of Racket's front end: macro
 expander, reader, and module systems. A copy of this implementation is
 extracted and built into the Racket executable, so normally this
 package's modules are not run directly. The expander or reader can be
@@ -92,31 +92,6 @@ Running:
    Expands and extracts <file-path> as a single linklet, compiles it
    and then writes the bytecode into <outfile-path>.
 
- % racket bootstrap-run.rkt -c <dir> -O <checkout-dir>/racket
-
-   Compiles the expander to source files in <dir> --- note that
-   "bootstrap-run.rkt" must be used to get source compiles --- and
-   writes the flattened linklet to "startup.inc" in a Git checkout of
-   a linklet-based Racket. Be sure to increment the target Racket
-   version if you change the serialization of syntax objects or the
-   linklet protocol.
-
-   When you `make`, then "startup.inc" will be automatically compiled
-   to bytecode for for embedding into the Racket executable. If you
-   change the expander in a way that makes existing compiled files
-   invalid, be sure to update "schvers.h". (Updating "schvers.h" is
-   important both for bytecode files and the makefile/preprocessor
-   dance that generates the bytecode version of the expander itself.)
-
- % make
-
-   A shortcut for the above: When this package resides in an existing
-   in-place build from the main Racket repo, then the makefile uses
-   that copy of Racket to build the expander and drop a replacement
-   into the "src" directory. Re-making the Racket tree will then use
-   the updated expander. You may have to manually discard
-   "compiled/cache-src" when things change.
-
  % make demo
  % make run ARGS="<arg> ..."
 
@@ -127,6 +102,48 @@ Running:
 
 ----------------------------------------
 
+Building Racket to use this expander:
+
+After you change the expander, you must perform an explicit build step
+to use it when making Racket CS or Racket BC. Normally, for that case,
+the expander would be modified as part of a Racket repo checkout.
+Then:
+
+ * For Racket CS, go to "racket/src/cs" in the repo and run `make`.
+   That will update files in "racket/src/cs/schemified", including
+   using the new expander to rebuild the Racket-implemented parts of
+   Racket CS that are in "../thread", "../io", etc.
+
+   After this step, a `make cs` in the top level of the Racket repo
+   will build Racket CS using the new expander.
+
+ * For Racket BC, run `make` here, which will update the file
+   "racket/src/bc/src/startup.inc". Then, when you build Racket BC,
+   "startup.inc" will be automatically compiled to bytecode for
+   embedding into the Racket BC executable.
+
+   After this step, a `make bc` in the top level of the Racket repo
+   will build Racket CS using the new expander.
+
+For either of these steps, the makefile will assume that Racket is
+already built in the surrounding checkout, so Racket can be run as
+`../../bin/racket`. Use `make RACKET=....` to use a different Racket
+build, but beware that the version of Racket must be essentially the
+same version as the target build.
+
+Before building new CS and BC executables, increment the target Racket
+version in "../version/racket_version.h" if you change the
+serialization of syntax objects or the linklet protocol. Updating
+"racket_version.h" is important both for bytecode files and the
+makefile/preprocessor dance that generates the bytecode version of the
+expander itself.
+
+The `make` step for Racket BC generates source files in
+"compiled/cache-src". In come cases (hopefully rare), you may have to
+manually discard "compiled/cache-src" when things change.
+
+----------------------------------------
+
 Roadmap to the implementation:
 
  read/ - the readers

racket/src/expander/run.rkt

@@ -77,7 +77,7 @@
     (set! extract? #t)
     (set! extract-to-c? #t)
     (linklet-compile-to-s-expr #t)
-    (set! print-extracted-to (build-path checkout-directory "src" "racket" "src" "startup.inc"))]
+    (set! print-extracted-to (build-path checkout-directory "src" "bc" "src" "startup.inc"))]
    #:once-each
    [("-k") dir "Use Racket checkout at <dir>"
     (set! checkout-directory (path->complete-path dir))]