reader: fix parsing of here strings

pkgs/racket-test-core/tests/racket/read.rktl

@@ -213,6 +213,12 @@
 (err/rt-test (readstr "\"\\uD800\\uDD\"") exn:fail:read?)
 (err/rt-test (readstr "\"\\uD800\\uDD1\"") exn:fail:read?)
 
+(test "abc" readstr "#<<EOS\nabc\nEOS\n")
+(test "abc" readstr "#<<EOS\nabc\nEOS")
+(test "ok\r\nmore\r" readstr "#<<EOS\r\nok\r\nmore\r\nEOS\r")
+(err/rt-test (readstr "#<<EOS\nabc\nEO") exn:fail:read?)
+(err/rt-test (readstr "#<<EOS\r\nabc\nEOS") exn:fail:read?)
+
 (test (bytes 7) readstr "#\"\\a\"")
 (test (bytes 8) readstr "#\"\\b\"")
 (test (bytes 9) readstr "#\"\\t\"")

racket/src/expander/read/string.rkt

@@ -171,6 +171,8 @@
   
   ;; Parse terminator
   (define full-terminator
+    (cons
+     #\newline
      (let loop ()
        (define c (read-char/special in config source))
        (cond
@@ -181,7 +183,7 @@
           (reader-error in config #:due-to c
                         "found non-character while reading `#<<`")]
          [(char=? c #\newline) null]
-       [else (cons c (loop))])))
+         [else (cons c (loop))]))))
   
   ;; Get string content
   (let loop ([terminator full-terminator] [terminator-accum null])

racket/src/racket/src/startup.inc

@@ -51999,6 +51999,8 @@ static const char *startup_source =
 "(let-values(((source_28)(read-config-source config_48)))"
 "(let-values(((accum-str_5)(accum-string-init! config_48)))"
 "(let-values(((full-terminator_0)"
+"(cons"
+" '#\\newline"
 "((letrec-values(((loop_112)"
 "(lambda()"
 "(begin"
@@ -52041,7 +52043,7 @@ static const char *startup_source =
 "(if(char=? c_87 '#\\newline)"
 "(let-values() null)"
 "(let-values()(cons c_87(loop_112)))))))))))"
-" loop_112))))"
+" loop_112)))))"
 "(let-values((()"
 "(begin"
 "((letrec-values(((loop_113)"