remove uses of scheme/* in src

Fixes windows snapshot builds.

racket/src/foreign/foreign.rktc

@@ -564,7 +564,7 @@ static Scheme_Object *utf16_pointer_to_ucs4_string(unsigned short *utf)
 
 (define types null)
 
-(require (for-syntax scheme/base))
+(require (for-syntax racket/base))
 
 (define (get-prop type prop)
   (cadr (assq prop (cdr (assq type types)))))

racket/src/foreign/rktc-utils.rkt

@@ -1,8 +1,8 @@
 ;; Preprocessor utilities for the .rktc file.
 
-#lang at-exp scheme/base
+#lang at-exp racket/base
 
-(require (for-syntax scheme/base) scheme/list scribble/text/output)
+(require (for-syntax racket/base) racket/list scribble/text/output)
 
 (provide maplines)
 (define (maplines #:semicolons? [semi? #t] fun . ls)

racket/src/racket/src/gen-jit-ts.rkt

@@ -1,5 +1,5 @@
-#lang at-exp scheme/base
+#lang at-exp racket/base
-(require scheme/string)
+(require racket/string)
 
 (define (char->type c)
   (case c

racket/src/racket/src/mk-uchar.rkt

@@ -12,7 +12,7 @@
 ;; in the "Unicode" directory. The file schuchar.inc will be
 ;; overwritten.
 
-(require scheme/list)
+(require racket/list)
 
 (define mark-cats '("Mn" "Mc" "Me"))
 (define letter-cats '("Lu" "Ll" "Lt" "Lm" "Lo"))

racket/src/racket/src/renumber.rkt

@@ -1,4 +1,4 @@
-#lang scheme/base
+#lang racket/base
 
 (define filename "stypes.h")
 

racket/src/racket/src/sstoinc.rkt

@@ -1,5 +1,5 @@
 
-#lang scheme/base
+#lang racket/base
 
 (define to-zo? (member "--zo" (vector->list (current-command-line-arguments))))
 

racket/src/worksp/mzcom/xform.rkt

@@ -1,4 +1,4 @@
-#lang scheme/base
+#lang racket/base
 
 (define cpp-flags "/D _CRT_SECURE_NO_DEPRECATE /D WIN32 /D _USE_DECLSPECS_FOR_SAL=0 /D _USE_ATTRIBUTES_FOR_SAL=0")
 (define includes "/I ../../racket/include /I . /I .. /I ../../mzcom")