diff --git a/src/mred/Makefile.in b/src/mred/Makefile.in
index 00dace9bbc..a167e57228 100644
--- a/src/mred/Makefile.in
+++ b/src/mred/Makefile.in
@@ -243,7 +243,7 @@ install_wx_xt:
 	cd ..; rm -f "$(bindir)/mred"
 	$(MAKE) @MRLIBINSTALL@
 	cd ..; $(ICP) mred/mred "$(bindir)"
-	$(MZSCHEME) -mvqu "$(srcdir)/../mzscheme/collects-path.ss" "$(prefix)/bin/mred" @COLLECTS_PATH@
+	$(MZSCHEME) -mvqu "$(srcdir)/../mzscheme/collects-path.ss" "$(prefix)/bin/mred@EXE_SUFFIX@" @COLLECTS_PATH@
 
 BUILDINFO=$(libpltdir)/buildinfo
 
@@ -294,7 +294,7 @@ install-lib3m:
 
 install-3m_wx_xt:
 	cd ..; $(ICP) mred/mred3m "$(bindir)"
-	$(MZSCHEME) -mvqu "$(srcdir)/../mzscheme/collects-path.ss" "$(bindir)/mred3m" @COLLECTS_PATH@
+	$(MZSCHEME) -mvqu "$(srcdir)/../mzscheme/collects-path.ss" "$(bindir)/mred3m@EXE_SUFFIX@" @COLLECTS_PATH@
 	$(MAKE) @MRLIBINSTALL@3m
 
 install-3m_wx_mac:
diff --git a/src/mzscheme/Makefile.in b/src/mzscheme/Makefile.in
index 644f341b9a..71572f1f60 100644
--- a/src/mzscheme/Makefile.in
+++ b/src/mzscheme/Makefile.in
@@ -38,6 +38,14 @@ FOREIGN_OBJSLIB = @FOREIGN_OBJSLIB@
 
 LLVM_DIR = ../llvm
 
+# About EXE_SUFFIX:
+#  Cygwin offers the illusion that binaries have no ".exe" suffix by
+#  having the file-open syscall open an ".exe" file for reading when
+#  (1) the given filename has no suffix, and (2) there's not a suffixless
+#  file present. However, Cygwin doesn't do that when opening a file for
+#  output, even when the output mode is 'update. So we need to explcitly
+#  add EXE_SUFFIX in a few places.
+
 ################################################################################
 
 bin: 
@@ -270,7 +278,7 @@ install:
 install-3m-basic:
 	cd ..; $(ICP) mzscheme/mzscheme3m $(bindir)/mzscheme3m
 	cd ..; $(ICP) mzscheme/mzdyn3m.o $(libpltdir)/mzdyn3m.o
-	./mzscheme -mvqu "$(srcdir)/collects-path.ss" "$(bindir)/mzscheme3m" @COLLECTS_PATH@
+	./mzscheme -mvqu "$(srcdir)/collects-path.ss" "$(bindir)/mzscheme3m@EXE_SUFFIX@" @COLLECTS_PATH@
 
 install-3m@NOT_OSX@:
 	$(MAKE) install-3m-basic
@@ -284,7 +292,7 @@ unix-install:
 	cd ..; $(ICP) mzscheme/libmzgc.@LIBSFX@ "$(libdir)/libmzgc.@LIBSFX@"
 	cd ..; $(ICP) mzscheme/libmzscheme.@LIBSFX@ "$(libdir)/libmzscheme.@LIBSFX@"
 	cd ..; $(ICP) mzscheme/mzscheme "$(bindir)/mzscheme"
-	./mzscheme -mvqu "$(srcdir)/collects-path.ss" "$(bindir)/mzscheme" @COLLECTS_PATH@
+	./mzscheme -mvqu "$(srcdir)/collects-path.ss" "$(bindir)/mzscheme@EXE_SUFFIX@" @COLLECTS_PATH@
 	cd ..; echo 'CC=@CC@' > $(BUILDINFO)
 	cd ..; echo 'CFLAGS=@CFLAGS@ @PREFLAGS@ @COMPFLAGS@' >> $(BUILDINFO)
 	cd ..; echo 'OPTIONS=@OPTIONS@' >> $(BUILDINFO)
diff --git a/src/mzscheme/sconfig.h b/src/mzscheme/sconfig.h
index 9b2584fc9f..d349e58364 100644
--- a/src/mzscheme/sconfig.h
+++ b/src/mzscheme/sconfig.h
@@ -620,6 +620,7 @@
 # define USE_CREATE_PIPE
 
 # define USE_MZ_CYGWIN_SETJMP
+# define USE_MZ_SETJMP
 
 # define USE_PLAIN_TIME
 # define USE_TOD_FOR_TIMEZONE
diff --git a/src/mzscheme/src/setjmpup.c b/src/mzscheme/src/setjmpup.c
index 2a10c2be58..9b874f427b 100644
--- a/src/mzscheme/src/setjmpup.c
+++ b/src/mzscheme/src/setjmpup.c
@@ -576,7 +576,7 @@ void scheme_ensure_stack_start(Scheme_Thread *p, void *d)
    as mzsj86.c, just in a slightly different syntax, and it
    probably only works with -O2. */
 
-int scheme_mz_setjmp(mz_jmp_buf b)
+int scheme_mz_setjmp(mz_pre_jmp_buf b)
 {
   asm("mov 4(%EBP), %ECX"); /* return address */
   asm("mov 8(%EBP), %EAX"); /* jmp_buf ptr */
@@ -591,7 +591,7 @@ int scheme_mz_setjmp(mz_jmp_buf b)
   return 0;
 }
 
-void scheme_mz_longjmp(mz_jmp_buf b, int v)
+void scheme_mz_longjmp(mz_pre_jmp_buf b, int v)
 {
   asm("mov 12(%EBP), %EAX"); /* return value */
   asm("mov 8(%EBP), %ECX");  /* jmp_buf */