diff --git a/src/worksp/.gitignore b/src/worksp/.gitignore
index bed63a0c70..534a74a53d 100644
--- a/src/worksp/.gitignore
+++ b/src/worksp/.gitignore
@@ -3,3 +3,6 @@
 */Debug
 */x64
 */*.user
+
+rbuildmode.obj
+rbuildmode.exe
diff --git a/src/worksp/README b/src/worksp/README
index ad3482af44..9e9cfe284a 100644
--- a/src/worksp/README
+++ b/src/worksp/README
@@ -263,7 +263,7 @@ The libraries
     racket\lib\win32\msvc\libracketxxxxxxx.lib
     racket\lib\win32\msvc\libmzgcxxxxxxx.lib
 
-which are created by the mzsrc and gc projects, provide linking
+which are created by the libracket and libmzgc projects, provide linking
 information for using the libracket3mxxxxxxx.dll, libracketxxxxxxx.dll,
 and libmzgcxxxxxxx.dll DLLs.  The versioning script adjusts the names,
 as described above.
diff --git a/src/worksp/build.bat b/src/worksp/build.bat
index c9f5c3defd..e2859272f0 100644
--- a/src/worksp/build.bat
+++ b/src/worksp/build.bat
@@ -1,40 +1,60 @@
+setlocal
+
+cl rbuildmode.c
+rbuildmode.exe
+if errorlevel 1 (set BUILDMODE=win32) else (set BUILDMODE=x64)
+
 cd racket
-devenv racket.sln /Build Release
+devenv racket.sln /Build "Release|%BUILDMODE%"
+if errorlevel 1 exit /B 1
 cd ..\gracket
-devenv gracket.sln /Build Release
+devenv gracket.sln /Build "Release|%BUILDMODE%"
+if errorlevel 1 exit /B 1
 cd ..
 
 cd gc2
 ..\..\..\racketcgc -cu make.rkt
+if errorlevel 1 exit /B 1
 cd ..
 
 ..\..\racket -cu ..\get-libs.rkt core ..\..\lib
+if errorlevel 1 exit /B 1
 ..\..\racket -cu ..\get-libs.rkt gui  ..\..\lib
+if errorlevel 1 exit /B 1
 
 cd mzstart
-devenv mzstart.sln /Build Release
+devenv mzstart.sln /Build "Release|%BUILDMODE%"
+if errorlevel 1 exit /B 1
 cd ..\mrstart
-devenv mrstart.sln /Build Release
+devenv mrstart.sln /Build "Release|%BUILDMODE%"
+if errorlevel 1 exit /B 1
 cd ..
 
 cd mzcom
-devenv mzcom.sln /Build Release
+devenv mzcom.sln /Build "Release|%BUILDMODE%"
+if errorlevel 1 exit /B 1
 cd ..\libmysterx
-devenv libmysterx.sln /Build Release
+devenv libmysterx.sln /Build "Release|%BUILDMODE%"
+if errorlevel 1 exit /B 1
 cd ..
 
 cd libmysterx
 ..\..\..\racket -cu xform.rkt
+if errorlevel 1 exit /B 1
 cd ..
 
 cd mzcom
 ..\..\..\racket -cu xform.rkt
+if errorlevel 1 exit /B 1
 cd ..
 
 cd mzcom
-devenv mzcom.sln /Build 3m
+devenv mzcom.sln /Build "3m|%BUILDMODE%"
+if errorlevel 1 exit /B 1
 cd ..\libmysterx
-devenv libmysterx.sln /Build 3m
+devenv libmysterx.sln /Build "3m|%BUILDMODE%"
+if errorlevel 1 exit /B 1
 cd ..
 
 ..\..\racket -l setup -N "raco setup"
+if errorlevel 1 exit /B 1
diff --git a/src/worksp/libmysterx/libmysterx.vcproj b/src/worksp/libmysterx/libmysterx.vcproj
index f5531232f3..374e72e6c4 100644
--- a/src/worksp/libmysterx/libmysterx.vcproj
+++ b/src/worksp/libmysterx/libmysterx.vcproj
@@ -155,7 +155,7 @@
 				BrowseInformation="1"
 				WarningLevel="3"
 				SuppressStartupBanner="true"
-				Detect64BitPortabilityProblems="true"
+				Detect64BitPortabilityProblems="false"
 				DebugInformationFormat="3"
 			/>
 			<Tool
@@ -341,7 +341,7 @@
 				UsePrecompiledHeader="0"
 				WarningLevel="3"
 				SuppressStartupBanner="true"
-				Detect64BitPortabilityProblems="true"
+				Detect64BitPortabilityProblems="false"
 				DebugInformationFormat="0"
 				CompileAs="0"
 			/>
@@ -529,7 +529,7 @@
 				UsePrecompiledHeader="0"
 				WarningLevel="3"
 				SuppressStartupBanner="true"
-				Detect64BitPortabilityProblems="true"
+				Detect64BitPortabilityProblems="false"
 				DebugInformationFormat="0"
 				CompileAs="0"
 			/>
diff --git a/src/worksp/libmysterx/myspage/myspage.vcproj b/src/worksp/libmysterx/myspage/myspage.vcproj
index 3feb14cd32..9e7d595151 100644
--- a/src/worksp/libmysterx/myspage/myspage.vcproj
+++ b/src/worksp/libmysterx/myspage/myspage.vcproj
@@ -112,8 +112,6 @@
 			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				Description="Register $(ProjectName).dll"
-				CommandLine="REGSVR32 /s ..\..\..\..\lib\$(ProjectName).dll"
 			/>
 		</Configuration>
 		<Configuration
@@ -162,7 +160,7 @@
 				UsePrecompiledHeader="0"
 				BrowseInformation="1"
 				WarningLevel="4"
-				Detect64BitPortabilityProblems="true"
+				Detect64BitPortabilityProblems="false"
 				DebugInformationFormat="3"
 			/>
 			<Tool
@@ -211,8 +209,6 @@
 			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				Description="Register $(ProjectName).dll"
-				CommandLine="REGSVR32 /s ..\..\..\..\lib\$(ProjectName).dll"
 			/>
 		</Configuration>
 		<Configuration
@@ -313,8 +309,6 @@
 			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				Description="Register $(ProjectName).dll"
-				CommandLine="REGSVR32 /s ..\..\..\..\lib\$(ProjectName).dll"
 			/>
 		</Configuration>
 		<Configuration
@@ -366,7 +360,7 @@
 				ProgramDataBaseFileName=""
 				WarningLevel="4"
 				SuppressStartupBanner="true"
-				Detect64BitPortabilityProblems="true"
+				Detect64BitPortabilityProblems="false"
 				DebugInformationFormat="0"
 			/>
 			<Tool
@@ -416,8 +410,6 @@
 			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				Description="Register $(ProjectName).dll"
-				CommandLine="REGSVR32 /s ..\..\..\..\lib\$(ProjectName).dll"
 			/>
 		</Configuration>
 	</Configurations>
diff --git a/src/worksp/libmysterx/myssink/myssink.vcproj b/src/worksp/libmysterx/myssink/myssink.vcproj
index 653ba09108..eaca508074 100644
--- a/src/worksp/libmysterx/myssink/myssink.vcproj
+++ b/src/worksp/libmysterx/myssink/myssink.vcproj
@@ -112,8 +112,6 @@
 			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				Description="Register $(ProjectName).dll"
-				CommandLine="REGSVR32 /s ..\..\..\..\lib\$(ProjectName).dll"
 			/>
 		</Configuration>
 		<Configuration
@@ -160,7 +158,7 @@
 				UsePrecompiledHeader="0"
 				BrowseInformation="1"
 				WarningLevel="4"
-				Detect64BitPortabilityProblems="true"
+				Detect64BitPortabilityProblems="false"
 				DebugInformationFormat="3"
 				CompileAs="2"
 			/>
@@ -211,8 +209,6 @@
 			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				Description="Register $(ProjectName).dll"
-				CommandLine="REGSVR32 /s ..\..\..\..\lib\$(ProjectName).dll"
 			/>
 		</Configuration>
 		<Configuration
@@ -315,8 +311,6 @@
 			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				Description="Register $(ProjectName).dll"
-				CommandLine="REGSVR32 /s ..\..\..\..\lib\$(ProjectName).dll"
 			/>
 		</Configuration>
 		<Configuration
@@ -368,7 +362,7 @@
 				ProgramDataBaseFileName=""
 				WarningLevel="4"
 				SuppressStartupBanner="true"
-				Detect64BitPortabilityProblems="true"
+				Detect64BitPortabilityProblems="false"
 				DebugInformationFormat="0"
 				CompileAs="2"
 			/>
@@ -419,8 +413,6 @@
 			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				Description="Register $(ProjectName).dll"
-				CommandLine="REGSVR32 /s ..\..\..\..\lib\$(ProjectName).dll"
 			/>
 		</Configuration>
 	</Configurations>
diff --git a/src/worksp/libracket/libracket.vcproj b/src/worksp/libracket/libracket.vcproj
index 9d182cf4fe..1de06086dc 100644
--- a/src/worksp/libracket/libracket.vcproj
+++ b/src/worksp/libracket/libracket.vcproj
@@ -45,7 +45,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="0"
-				AdditionalIncludeDirectories="..,..\..\racket\include,..\..\racket\src,..\..\foreign\libffi_msvc,$(NOINHERIT)"
+				AdditionalIncludeDirectories="..,..\..\racket\include,..\..\racket\src,$(NOINHERIT)"
 				PreprocessorDefinitions="WIN32;_DEBUG;_WINDOWS;_USRDLL;GC_DLL;__STDC__;LIBMZ_EXPORTS;_CRT_SECURE_NO_DEPRECATE"
 				BasicRuntimeChecks="3"
 				RuntimeLibrary="1"
@@ -130,7 +130,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="0"
-				AdditionalIncludeDirectories="..,..\..\racket\include,..\..\racket\src,..\..\foreign\libffi_msvc,$(NOINHERIT)"
+				AdditionalIncludeDirectories="..,..\..\racket\include,..\..\racket\src,$(NOINHERIT)"
 				PreprocessorDefinitions="WIN32;_DEBUG;_WINDOWS;_USRDLL;GC_DLL;__STDC__;LIBMZ_EXPORTS;_CRT_SECURE_NO_DEPRECATE"
 				BasicRuntimeChecks="3"
 				RuntimeLibrary="1"
diff --git a/src/worksp/rbuildmode.c b/src/worksp/rbuildmode.c
new file mode 100644
index 0000000000..a86c6d0808
--- /dev/null
+++ b/src/worksp/rbuildmode.c
@@ -0,0 +1,8 @@
+
+int main() {
+#ifdef _WIN64
+  return 0;
+#else
+  return 1;
+#endif
+}