repair handling of PLTCOMPILEDROOTS

Commit a110c58e52 broke the interaction with `PLTCOMPILEDROOTS`.
Instead of reverting to the old behavior that coerced 'same to a path,
this change makes `path-list-string->path-list` a little more
flexible.

Closes #3704

pkgs/racket-doc/scribblings/reference/filesystem.scrbl

@@ -252,8 +252,8 @@ by @racket[kind], which must be one of the following:
                                    with similar adjustments for Mac OS.}]}
 
 @defproc[(path-list-string->path-list [str (or/c string? bytes?)]
-                                      [default-path-list (listof path?)])
-         (listof path?)]{
+                                      [default-path-list (listof (or/c path? 'same))])
+         (listof (or/c path? 'same))]{
 
 Parses a string or byte string containing a list of paths, and returns
 a list of path strings. On @|AllUnix|, paths in a path list are
@@ -262,7 +262,10 @@ separated by a @litchar{:}; on Windows, paths are separated by a
 list contains an empty path, the list
 @racket[default-path-list] is spliced into the returned list of
 paths. Parts of @racket[str] that do not form a valid path are not
-included in the returned list.}
+included in the returned list.
+
+@history[#:changed "8.0.0.10" @elem{Changed to allow @racket['same] in
+                                    @racket[default-path-list].}]}
 
 
 @defproc[(find-executable-path [program path-string?]

racket/collects/racket/private/path-list.rkt

@@ -27,7 +27,7 @@
                 (string? s))
       (raise-argument-error 'path-list-string->path-list "(or/c bytes? string?)" s))
     (unless (and (list? default)
-                 (andmap path? default))
+                 (andmap (lambda (p) (or (eq? p 'same) path?)) default))
       (raise-argument-error 'path-list-string->path-list "(listof path?)" default))
     (init-rx:path-list!)
     (let loop ([s (if (string? s)

racket/src/bc/src/startup.inc

@@ -556,7 +556,11 @@ static const char *startup_source =
 "(if(let-values(((or-part_0)(bytes? s_0)))(if or-part_0 or-part_0(string? s_0)))"
 "(void)"
 "          (let-values () (raise-argument-error 'path-list-string->path-list \"(or/c bytes? string?)\" s_0)))"
-"(if(if(list? default_0)(andmap path? default_0) #f)"
+"(if(if(list? default_0)"
+"(andmap"
+"(lambda(p_0)(let-values(((or-part_0)(eq? p_0 'same)))(if or-part_0 or-part_0 path?)))"
+" default_0)"
+" #f)"
 "(void)"
 "          (let-values () (raise-argument-error 'path-list-string->path-list \"(listof path?)\" default_0)))"
 "(init-rx:path-list!)"

racket/src/cs/schemified/expander.scm

@@ -1093,7 +1093,13 @@
          'path-list-string->path-list
          "(or/c bytes? string?)"
          s_0))
-      (if (if (list? default_0) (andmap path? default_0) #f)
+      (if (if (list? default_0)
+            (andmap
+             (lambda (p_0)
+               (let ((or-part_0 (eq? p_0 'same)))
+                 (if or-part_0 or-part_0 path?)))
+             default_0)
+            #f)
         (void)
         (raise-argument-error
          'path-list-string->path-list