diff --git a/prism/Makefile b/prism/Makefile
index a23fda12..c7497cb2 100644
--- a/prism/Makefile
+++ b/prism/Makefile
@@ -203,7 +203,7 @@ ifeq ($(OSTYPE),cygwin)
 	ifeq ($(ARCH),x86_64)
 		C = /usr/bin/x86_64-w64-mingw32-gcc
 		CPP = /usr/bin/x86_64-w64-mingw32-g++
-		CUDD_XCFLAGS = -march=x86_64 -fPIC -DPIC -malign-double -DHAVE_IEEE_754 -DHAVE_GETRLIMIT=0 -DRLIMIT_DATA_DEFAULT=268435456 -DHAVE_SYS_RESOURCE_H=0 -DHAVE_SYS_WAIT_H=0 -DSIZEOF_VOID_P=8 -DSIZEOF_LONG=8 $(DEBUG) -static-libgcc -static-libstdc++
+		CUDD_XCFLAGS = -fPIC -DPIC -malign-double -DHAVE_IEEE_754 -DHAVE_GETRLIMIT=0 -DRLIMIT_DATA_DEFAULT=268435456 -DHAVE_SYS_RESOURCE_H=0 -DHAVE_SYS_WAIT_H=0 -DSIZEOF_VOID_P=8 -DSIZEOF_LONG=4 -fpermissive $(DEBUG) -static-libgcc -static-libstdc++
 		CFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE)
 		CPPFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE)
 		LDFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE) -Wl,--add-stdcall-alias