diff --git a/dlls/winmm/Makefile.in b/dlls/winmm/Makefile.in
index c515a3aba2e..81519a58853 100644
--- a/dlls/winmm/Makefile.in
+++ b/dlls/winmm/Makefile.in
@@ -1,4 +1,3 @@
-EXTRADEFS = -D_WINMM_
 MODULE    = winmm.dll
 IMPORTLIB = winmm
 IMPORTS   = uuid user32 advapi32 ole32 msacm32