diff --git a/win/build-deps.cmd b/win/build-deps.cmd
index 1c948459c6..d1f5daabd8 100644
--- a/win/build-deps.cmd
+++ b/win/build-deps.cmd
@@ -363,7 +363,9 @@ if "%VS_VER%"=="2017" (
   set mpfr_sln=build.vs19
   set orig_platform_toolset=v142
 )
-powershell -c "get-childitem %DEPENDENCY_DIR%\%mpfr_sln% -recurse -include *.vcxproj | select -expand fullname | foreach { (Get-Content $_) -replace '%orig_platform_toolset%', 'v%VC_VER:.=%' | Set-Content $_ }"
+set target_platform_toolset=v%VC_VER:.=%
+IF DEFINED VS_TOOLSET set target_platform_toolset=%VS_TOOLSET%
+powershell -c "get-childitem %DEPENDENCY_DIR%\%mpfr_sln% -recurse -include *.vcxproj | select -expand fullname | foreach { (Get-Content $_) -replace '%orig_platform_toolset%', '%target_platform_toolset%' | Set-Content $_ }"
 :: mpfr's vcxproj files only define Debug/Release configurations (no RelWithDebInfo/MinSizeRel).
 call :BuildSolution "%DEPENDENCY_DIR%\%mpfr_sln%\lib_mpfr.sln" %DEBUG_OR_RELEASE% lib_mpfr
 IF NOT %ERRORLEVEL%==0 GOTO :Error