diff --git a/src/Make_cyg.mak b/src/Make_cyg.mak
index 0ca7115..9cc3784 100644
--- a/src/Make_cyg.mak
+++ b/src/Make_cyg.mak
@@ -1,6 +1,6 @@
 #
 # Makefile for VIM on Win32, using Cygnus gcc
-# Last updated by Dan Sharp.  Last Change: 2010 Feb 24
+# Last updated by Dan Sharp.  Last Change: 2010 Nov 03
 #
 # Also read INSTALLpc.txt!
 #
@@ -27,6 +27,7 @@
 #   MZSCHEME_VER      define to version of MzScheme being used (209_000)
 #   DYNAMIC_MZSCHEME  no or yes: use yes to load the MzScheme DLLs dynamically (yes)
 #   MZSCHEME_DLLS     path to MzScheme DLLs (libmzgc and libmzsch), for "static" build.
+#   MZSCHEME_USE_RACKET  define to use "racket" instead of "mzsch".
 # LUA	define to path to Lua dir to get Lua support (not defined)
 #   LUA_VER	    define to version of Lua being used (51)
 #   DYNAMIC_LUA  no or yes: use yes to load the Lua DLL dynamically (yes)
@@ -254,16 +255,22 @@
 MZSCHEME_GENERATE_BASE=no
 endif
 
+ifndef MZSCHEME_USE_RACKET
+MZSCHEME_MAIN_LIB=mzsch
+else
+MZSCHEME_MAIN_LIB=racket
+endif
+
 ifeq (yes, $(DYNAMIC_MZSCHEME))
-DEFINES += -DDYNAMIC_MZSCHEME -DDYNAMIC_MZSCH_DLL=\"libmzsch$(MZSCHEME_VER).dll\" -DDYNAMIC_MZGC_DLL=\"libmzgc$(MZSCHEME_VER).dll\"
+DEFINES += -DDYNAMIC_MZSCHEME -DDYNAMIC_MZSCH_DLL=\"lib$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER).dll\" -DDYNAMIC_MZGC_DLL=\"libmzgc$(MZSCHEME_VER).dll\"
 else
 ifndef MZSCHEME_DLLS
 MZSCHEME_DLLS = $(MZSCHEME)
 endif
 ifeq (yes,$(MZSCHEME_PRECISE_GC))
-MZSCHEME_LIB=-lmzsch$(MZSCHEME_VER)
+MZSCHEME_LIB=-l$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER)
 else
-MZSCHEME_LIB = -lmzsch$(MZSCHEME_VER) -lmzgc$(MZSCHEME_VER)
+MZSCHEME_LIB = -l$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER) -lmzgc$(MZSCHEME_VER)
 endif
 EXTRA_LIBS += -L$(MZSCHEME_DLLS) -L$(MZSCHEME_DLLS)/lib $(MZSCHEME_LIB)
 endif
diff --git a/src/Make_ming.mak b/src/Make_ming.mak
index a6fd170..c98fc42 100644
--- a/src/Make_ming.mak
+++ b/src/Make_ming.mak
@@ -141,11 +141,17 @@
 MZSCHEME_GENERATE_BASE=no
 endif
 
+ifndef MZSCHEME_USE_RACKET
+MZSCHEME_MAIN_LIB=mzsch
+else
+MZSCHEME_MAIN_LIB=racket
+endif
+
 ifeq (no,$(DYNAMIC_MZSCHEME))
 ifeq (yes,$(MZSCHEME_PRECISE_GC))
-MZSCHEME_LIB=-lmzsch$(MZSCHEME_VER)
+MZSCHEME_LIB=-l$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER)
 else
-MZSCHEME_LIB = -lmzsch$(MZSCHEME_VER) -lmzgc$(MZSCHEME_VER)
+MZSCHEME_LIB = -l$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER) -lmzgc$(MZSCHEME_VER)
 endif
 # the modern MinGW can dynamically link to dlls directly.
 # point MZSCHEME_DLLS to where you put libmzschXXXXXXX.dll and libgcXXXXXXX.dll
@@ -343,7 +349,7 @@
 ifdef MZSCHEME
 CFLAGS += -I$(MZSCHEME)/include -DFEAT_MZSCHEME -DMZSCHEME_COLLECTS=\"$(MZSCHEME)/collects\"
 ifeq (yes, $(DYNAMIC_MZSCHEME))
-CFLAGS += -DDYNAMIC_MZSCHEME -DDYNAMIC_MZSCH_DLL=\"libmzsch$(MZSCHEME_VER).dll\" -DDYNAMIC_MZGC_DLL=\"libmzgc$(MZSCHEME_VER).dll\"
+CFLAGS += -DDYNAMIC_MZSCHEME -DDYNAMIC_MZSCH_DLL=\"lib$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER).dll\" -DDYNAMIC_MZGC_DLL=\"libmzgc$(MZSCHEME_VER).dll\"
 endif
 endif
 
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index 9d34633..a353a9c 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -705,12 +705,18 @@
 MZSCHEME_VER = 205_000
 !endif
 CFLAGS = $(CFLAGS) -DFEAT_MZSCHEME -I $(MZSCHEME)\include
-!if EXIST("$(MZSCHEME)\collects\scheme\base.ss")
-# for MzScheme 4.x we need to include byte code for basic Scheme stuff
+!if EXIST("$(MZSCHEME)\collects\scheme\base.ss") \
+	|| EXIST("$(MZSCHEME)\collects\scheme\base.rkt") 
+# for MzScheme >= 4 we need to include byte code for basic Scheme stuff
 MZSCHEME_EXTRA_DEP = mzscheme_base.c
 CFLAGS = $(CFLAGS) -DINCLUDE_MZSCHEME_BASE
 !endif
-!if EXIST("$(MZSCHEME)\lib\msvc\libmzsch$(MZSCHEME_VER).lib") \
+!if EXIST("$(MZSCHEME)\lib\msvc\libmzsch$(MZSCHEME_VER).lib")
+MZSCHEME_MAIN_LIB=mzsch
+!else
+MZSCHEME_MAIN_LIB=racket
+!endif
+!if EXIST("$(MZSCHEME)\lib\msvc\lib$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER).lib") \
 	&& !EXIST("$(MZSCHEME)\lib\msvc\libmzgc$(MZSCHEME_VER).lib")
 !message Building with Precise GC
 MZSCHEME_PRECISE_GC = yes
@@ -722,7 +728,7 @@
 !endif
 !message MzScheme DLLs will be loaded dynamically
 CFLAGS = $(CFLAGS) -DDYNAMIC_MZSCHEME \
-		-DDYNAMIC_MZSCH_DLL=\"libmzsch$(MZSCHEME_VER).dll\" \
+		-DDYNAMIC_MZSCH_DLL=\"lib$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER).dll\" \
 		-DDYNAMIC_MZGC_DLL=\"libmzgc$(MZSCHEME_VER).dll\"
 !else
 !if "$(MZSCHEME_DEBUG)" == "yes"
@@ -730,10 +736,10 @@
 !endif
 !if "$(MZSCHEME_PRECISE_GC)" == "yes"
 # Precise GC does not use separate dll
-MZSCHEME_LIB = $(MZSCHEME)\lib\msvc\libmzsch$(MZSCHEME_VER).lib
+MZSCHEME_LIB = $(MZSCHEME)\lib\msvc\lib$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER).lib
 !else
 MZSCHEME_LIB = $(MZSCHEME)\lib\msvc\libmzgc$(MZSCHEME_VER).lib \
-		$(MZSCHEME)\lib\msvc\libmzsch$(MZSCHEME_VER).lib
+		$(MZSCHEME)\lib\msvc\lib$(MZSCHEME_MAIN_LIB)$(MZSCHEME_VER).lib
 !endif
 !endif
 MZSCHEME_OBJ = $(OUTDIR)\if_mzsch.obj
diff --git a/src/auto/configure b/src/auto/configure
index 87e6b8e..f18f5e5 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -4862,16 +4862,36 @@
       else
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if scheme.h can be found in /usr/include/plt/" >&5
-$as_echo_n "checking if scheme.h can be found in /usr/include/plt/... " >&6; }
-	if test -f /usr/include/plt/scheme.h; then
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if scheme.h can be found in $vi_cv_path_mzscheme_pfx/include/racket" >&5
+$as_echo_n "checking if scheme.h can be found in $vi_cv_path_mzscheme_pfx/include/racket... " >&6; }
+	if test -f $vi_cv_path_mzscheme_pfx/include/racket/scheme.h; then
 	  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
-	  SCHEME_INC=/usr/include/plt
+	  SCHEME_INC=${vi_cv_path_mzscheme_pfx}/include/racket
 	else
 	  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-	  vi_cv_path_mzscheme_pfx=
+	  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if scheme.h can be found in /usr/include/plt/" >&5
+$as_echo_n "checking if scheme.h can be found in /usr/include/plt/... " >&6; }
+	  if test -f /usr/include/plt/scheme.h; then
+	    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+	    SCHEME_INC=/usr/include/plt
+	  else
+	    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+	    { $as_echo "$as_me:${as_lineno-$LINENO}: checking if scheme.h can be found in /usr/include/racket/" >&5
+$as_echo_n "checking if scheme.h can be found in /usr/include/racket/... " >&6; }
+	    if test -f /usr/include/racket/scheme.h; then
+	      { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+	      SCHEME_INC=/usr/include/racket
+	    else
+	      { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+	      vi_cv_path_mzscheme_pfx=
+	    fi
+	  fi
 	fi
       fi
     fi
@@ -4883,12 +4903,22 @@
     elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libmzscheme3m.a"; then
       MZSCHEME_LIBS="${vi_cv_path_mzscheme_pfx}/lib/libmzscheme3m.a"
       MZSCHEME_CFLAGS="-DMZ_PRECISE_GC"
-    elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libmzgc.a"; then
+    elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libracket3m.a"; then
+      MZSCHEME_LIBS="${vi_cv_path_mzscheme_pfx}/lib/libracket3m.a"
+      MZSCHEME_CFLAGS="-DMZ_PRECISE_GC"
+    elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libracket.a"; then
+      MZSCHEME_LIBS="${vi_cv_path_mzscheme_pfx}/lib/libracket.a ${vi_cv_path_mzscheme_pfx}/lib/libmzgc.a"
+    elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libmzscheme.a"; then
       MZSCHEME_LIBS="${vi_cv_path_mzscheme_pfx}/lib/libmzscheme.a ${vi_cv_path_mzscheme_pfx}/lib/libmzgc.a"
     else
             if test -f "${vi_cv_path_mzscheme_pfx}/lib/libmzscheme3m.so"; then
         MZSCHEME_LIBS="-L${vi_cv_path_mzscheme_pfx}/lib -lmzscheme3m"
 	MZSCHEME_CFLAGS="-DMZ_PRECISE_GC"
+      elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libracket3m.so"; then
+        MZSCHEME_LIBS="-L${vi_cv_path_mzscheme_pfx}/lib -lracket3m"
+	MZSCHEME_CFLAGS="-DMZ_PRECISE_GC"
+      elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libracket.so"; then
+        MZSCHEME_LIBS="-L${vi_cv_path_mzscheme_pfx}/lib -lracket -lmzgc"
       else
         MZSCHEME_LIBS="-L${vi_cv_path_mzscheme_pfx}/lib -lmzscheme -lmzgc"
       fi
@@ -4901,10 +4931,20 @@
     fi
     if test -d $vi_cv_path_mzscheme_pfx/lib/plt/collects; then
       SCHEME_COLLECTS=lib/plt/
+    else
+      if test -d $vi_cv_path_mzscheme_pfx/lib/racket/collects; then
+	SCHEME_COLLECTS=lib/racket/
+      fi
     fi
     if test -f "${vi_cv_path_mzscheme_pfx}/${SCHEME_COLLECTS}collects/scheme/base.ss" ; then
-            MZSCHEME_EXTRA="mzscheme_base.c"
-      MZSCHEME_CFLAGS="${MZSCHEME_CFLAGS} -DINCLUDE_MZSCHEME_BASE"
+      MZSCHEME_EXTRA="mzscheme_base.c"
+    else
+      if test -f "${vi_cv_path_mzscheme_pfx}/${SCHEME_COLLECTS}collects/scheme/base.rkt" ; then
+	MZSCHEME_EXTRA="mzscheme_base.c"
+      fi
+    fi
+    if test "X$MZSCHEME_EXTRA" != "X" ; then
+            MZSCHEME_CFLAGS="${MZSCHEME_CFLAGS} -DINCLUDE_MZSCHEME_BASE"
       MZSCHEME_MZC="${vi_cv_path_mzscheme_pfx}/bin/mzc"
     fi
     MZSCHEME_CFLAGS="${MZSCHEME_CFLAGS} -I${SCHEME_INC} \
diff --git a/src/configure.in b/src/configure.in
index e7794f1..27bad25 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -568,13 +568,27 @@
 	SCHEME_INC=${vi_cv_path_mzscheme_pfx}/include/plt
       else
 	AC_MSG_RESULT(no)
-	AC_MSG_CHECKING(if scheme.h can be found in /usr/include/plt/)
-	if test -f /usr/include/plt/scheme.h; then
+	AC_MSG_CHECKING(if scheme.h can be found in $vi_cv_path_mzscheme_pfx/include/racket)
+	if test -f $vi_cv_path_mzscheme_pfx/include/racket/scheme.h; then
 	  AC_MSG_RESULT(yes)
-	  SCHEME_INC=/usr/include/plt
+	  SCHEME_INC=${vi_cv_path_mzscheme_pfx}/include/racket
 	else
 	  AC_MSG_RESULT(no)
-	  vi_cv_path_mzscheme_pfx=
+	  AC_MSG_CHECKING(if scheme.h can be found in /usr/include/plt/)
+	  if test -f /usr/include/plt/scheme.h; then
+	    AC_MSG_RESULT(yes)
+	    SCHEME_INC=/usr/include/plt
+	  else
+	    AC_MSG_RESULT(no)
+	    AC_MSG_CHECKING(if scheme.h can be found in /usr/include/racket/)
+	    if test -f /usr/include/racket/scheme.h; then
+	      AC_MSG_RESULT(yes)
+	      SCHEME_INC=/usr/include/racket
+	    else
+	      AC_MSG_RESULT(no)
+	      vi_cv_path_mzscheme_pfx=
+	    fi
+	  fi
 	fi
       fi
     fi
@@ -586,13 +600,23 @@
     elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libmzscheme3m.a"; then
       MZSCHEME_LIBS="${vi_cv_path_mzscheme_pfx}/lib/libmzscheme3m.a"
       MZSCHEME_CFLAGS="-DMZ_PRECISE_GC"
-    elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libmzgc.a"; then
+    elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libracket3m.a"; then
+      MZSCHEME_LIBS="${vi_cv_path_mzscheme_pfx}/lib/libracket3m.a"
+      MZSCHEME_CFLAGS="-DMZ_PRECISE_GC"
+    elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libracket.a"; then
+      MZSCHEME_LIBS="${vi_cv_path_mzscheme_pfx}/lib/libracket.a ${vi_cv_path_mzscheme_pfx}/lib/libmzgc.a"
+    elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libmzscheme.a"; then
       MZSCHEME_LIBS="${vi_cv_path_mzscheme_pfx}/lib/libmzscheme.a ${vi_cv_path_mzscheme_pfx}/lib/libmzgc.a"
     else
       dnl Using shared objects
       if test -f "${vi_cv_path_mzscheme_pfx}/lib/libmzscheme3m.so"; then
         MZSCHEME_LIBS="-L${vi_cv_path_mzscheme_pfx}/lib -lmzscheme3m"
 	MZSCHEME_CFLAGS="-DMZ_PRECISE_GC"
+      elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libracket3m.so"; then
+        MZSCHEME_LIBS="-L${vi_cv_path_mzscheme_pfx}/lib -lracket3m"
+	MZSCHEME_CFLAGS="-DMZ_PRECISE_GC"
+      elif test -f "${vi_cv_path_mzscheme_pfx}/lib/libracket.so"; then
+        MZSCHEME_LIBS="-L${vi_cv_path_mzscheme_pfx}/lib -lracket -lmzgc"
       else
         MZSCHEME_LIBS="-L${vi_cv_path_mzscheme_pfx}/lib -lmzscheme -lmzgc"
       fi
@@ -607,10 +631,20 @@
     fi
     if test -d $vi_cv_path_mzscheme_pfx/lib/plt/collects; then
       SCHEME_COLLECTS=lib/plt/
+    else
+      if test -d $vi_cv_path_mzscheme_pfx/lib/racket/collects; then
+	SCHEME_COLLECTS=lib/racket/
+      fi
     fi
     if test -f "${vi_cv_path_mzscheme_pfx}/${SCHEME_COLLECTS}collects/scheme/base.ss" ; then
-      dnl need to generate bytecode for MzScheme base
       MZSCHEME_EXTRA="mzscheme_base.c"
+    else
+      if test -f "${vi_cv_path_mzscheme_pfx}/${SCHEME_COLLECTS}collects/scheme/base.rkt" ; then
+	MZSCHEME_EXTRA="mzscheme_base.c"
+      fi
+    fi
+    if test "X$MZSCHEME_EXTRA" != "X" ; then
+      dnl need to generate bytecode for MzScheme base
       MZSCHEME_CFLAGS="${MZSCHEME_CFLAGS} -DINCLUDE_MZSCHEME_BASE"
       MZSCHEME_MZC="${vi_cv_path_mzscheme_pfx}/bin/mzc"
     fi
diff --git a/src/if_mzsch.c b/src/if_mzsch.c
index d940fd9..65873c9 100644
--- a/src/if_mzsch.c
+++ b/src/if_mzsch.c
@@ -794,9 +794,16 @@
 #endif
 }
 
+#if MZSCHEME_VERSION_MAJOR >= 500 && defined(WIN32) && defined(USE_THREAD_LOCAL)
+static __declspec(thread) void *tls_space;
+#endif
+
     void
 mzscheme_main(void)
 {
+#if MZSCHEME_VERSION_MAJOR >= 500 && defined(WIN32) && defined(USE_THREAD_LOCAL)
+    scheme_register_tls_space(&tls_space, 0);
+#endif
 #if defined(MZ_PRECISE_GC) && MZSCHEME_VERSION_MAJOR >= 400
     /* use trampoline for precise GC in MzScheme >= 4.x */
     scheme_main_setup(TRUE, mzscheme_env_main, 0, NULL);
diff --git a/src/version.c b/src/version.c
index adfe2a3..fbca25e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -715,6 +715,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    49,
+/**/
     48,
 /**/
     47,