diff --git a/dlls/msvcrt20/Makefile.in b/dlls/msvcrt20/Makefile.in
index 0696bfccea7..162062e985e 100644
--- a/dlls/msvcrt20/Makefile.in
+++ b/dlls/msvcrt20/Makefile.in
@@ -1,4 +1,3 @@
-EXTRADEFS = -DUSE_MSVCRT_PREFIX
 MODULE    = msvcrt20.dll
 IMPORTS   = msvcrt
 
diff --git a/dlls/msvcrt40/Makefile.in b/dlls/msvcrt40/Makefile.in
index aab9e2148bb..576d651c702 100644
--- a/dlls/msvcrt40/Makefile.in
+++ b/dlls/msvcrt40/Makefile.in
@@ -1,4 +1,3 @@
-EXTRADEFS = -DUSE_MSVCRT_PREFIX
 MODULE    = msvcrt40.dll
 
 EXTRADLLFLAGS = -mno-cygwin