add compile-omit-concatenate-support

Perform slightly less work on every fasl or unfasl of compiled code
that does not need to support `concatenate-object-files`.

original commit: 410985b062a3e2a4cc48da583167254d4adad2d2

csug/system.stex

@@ -2404,6 +2404,18 @@ referenced libraries are known to be present and already invoked, and
 only when it's worth saving the small overhead of representing and
 running the check.
 
+%----------------------------------------------------------------------------
+\entryheader
+\formdef{compile-omit-concatenate-support}{\categorythreadparameter}{compile-omit-concatenate-support}
+\listlibraries
+\endentryheader
+
+\noindent
+This boolean-valued parameter determines whether code compiled to a
+file or port includes information needed to support
+\scheme{concatenate-object-files}. Omitting the information can
+provide minor space and load-time savings for small compiled objects.
+
 
 \section{Source Directories and Files\label{SECTSYSTEMSOURCE}}
 

s/back.ss

@@ -214,6 +214,9 @@
          [(maximum) (constant COMPRESS-MAX)]
          [else ($oops who "~s is not a supported level" x)]))]))
 
+(define-who compile-omit-concatenate-support
+  ($make-thread-parameter #f (lambda (x) (and x #t))))
+
 (define-who debug-level
   ($make-thread-parameter
     1

s/compile.ss

@@ -780,8 +780,11 @@
                       [(revisit-stuff) x (c-print-fasl x op (constant fasl-type-revisit))]
                       [else (c-print-fasl x op (constant fasl-type-visit-revisit))]))
                   final*))
-              ; inserting #t after lpinfo as an end-of-header marker
-              (append lpinfo** (cons (list `(object #t)) final**)))))))))
+              (append lpinfo**
+                      (if (compile-omit-concatenate-support)
+                          final**
+                          ;; inserting #t after lpinfo as an end-of-header marker
+                          (cons (list `(object #t)) final**))))))))))
 
 (define (new-extension new-ext fn)
   (let ([old-ext (path-extension fn)])

s/primdata.ss

@@ -1230,6 +1230,7 @@
   (compile [sig [(sub-ptr) (sub-ptr environment) -> (ptr ...)]] [flags])
   (compile-file [sig [(pathname) (pathname pathname) (pathname pathname sub-symbol) -> (void)]] [flags true])
   (compile-library [sig [(pathname) (pathname pathname) (pathname pathname sub-symbol) -> (void)]] [flags true])
+  (compile-omit-concatenate-support [sig [() -> (boolean)] [(ptr) -> (void)]] [flags unrestricted])
   (compile-port [sig [(textual-input-port binary-output-port) (textual-input-port binary-output-port maybe-sfd) (textual-input-port binary-output-port maybe-sfd maybe-binary-output-port) (textual-input-port binary-output-port maybe-sfd maybe-binary-output-port maybe-textual-output-port) (textual-input-port binary-output-port maybe-sfd maybe-binary-output-port maybe-textual-output-port sub-symbol) (textual-input-port binary-output-port maybe-sfd maybe-binary-output-port maybe-textual-output-port sub-symbol maybe-binary-output-port) -> (void)]] [flags true])
   (compile-program [sig [(pathname) (pathname pathname) (pathname pathname sub-symbol) -> (list)]] [flags true])
   (compile-script [sig [(pathname) (pathname pathname) (pathname pathname sub-symbol) -> (void)]] [flags true])