Fix mingw32 build

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

kvm.h

@@ -53,7 +53,9 @@ int kvm_remove_breakpoint(CPUState *current_env, target_ulong addr,
                           target_ulong len, int type);
 void kvm_remove_all_breakpoints(CPUState *current_env);
 int kvm_update_guest_debug(CPUState *env, unsigned long reinject_trap);
+#ifndef _WIN32
 int kvm_set_signal_mask(CPUState *env, const sigset_t *sigset);
+#endif
 
 int kvm_pit_in_kernel(void);
 int kvm_irqchip_in_kernel(void);