Minor compilation fixes for Windows(R)(TM)

windows/thread.c

@@ -7,13 +7,21 @@
 */
 
 #include <stdio.h>
+#include <stdlib.h>
 
-void reset_procmask(void) {
+void
+reset_procmask(void) {
     printf("STUB: %s:%d", __FILE__, __LINE__);
 }
 
-int get_fake_if(void *ctx) {
+int
+get_fake_if(void *ctx) {
     (void)ctx;
     printf("STUB: %s:%d", __FILE__, __LINE__);
     return 0;
 }
+
+void
+system_shutdown(void) {
+    exit(0);
+}