Include math.h to fix some bugs on 32 bit windows.

src/core/ev.c

@@ -36,6 +36,7 @@
 #ifdef JANET_WINDOWS
 
 #include <windows.h>
+#include <math.h>
 
 #else
 

src/core/net.c

@@ -47,6 +47,7 @@
 #include <netinet/tcp.h>
 #include <netdb.h>
 #include <fcntl.h>
+#include <math.h>
 #endif
 
 /*