make WMB / MB safer on x86-64
make WMB / MB safer on x86-64

make it so that

if (foo)
	RMB;
else
	MB;

is always done correctly and without syntax surprises

xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS