diff --git a/mats/ftype.ms b/mats/ftype.ms
index 3e147cd1cf..e5c6a9d3d6 100644
--- a/mats/ftype.ms
+++ b/mats/ftype.ms
@@ -557,9 +557,9 @@
                        [(a6osx a6osx)
                         (system (format "cc -m64 -dynamiclib -o ~a ~a" testfile.so testfile.c))]
                        [(a6nt ta6nt)
-                        (system (format "..\\c\\vs.bat amd64 && cl /DWIN32 /Fe~a /LD /MD /nologo ~a" testfile.so testfile.c))]
+                        (system (format "set cl= && ..\\c\\vs.bat amd64 && cl /DWIN32 /Fe~a /LD /MD /nologo ~a" testfile.so testfile.c))]
                        [(i3nt ti3nt)
-                        (system (format "..\\c\\vs.bat x86 && cl /DWIN32 /Fe~a /LD /MD /nologo ~a" testfile.so testfile.c))]
+                        (system (format "set cl= && ..\\c\\vs.bat x86 && cl /DWIN32 /Fe~a /LD /MD /nologo ~a" testfile.so testfile.c))]
                        [(arm32le tarm32le)
                         (system (format "cc -fPIC -shared -o ~a ~a" testfile.so testfile.c))]
                        [else ; this should work for most intel-based systems that use gcc...