CE fix strange characters appearing at the end of file

ce/context.c

@@ -4,6 +4,7 @@
 #include <printf.h>
 #include <stdarg.h>
 #include <stddef.h>
+#include <string.h>
 
 void cprintf (struct context* context, const char* fmt, ...) {
   va_list args;
@@ -16,6 +17,7 @@ void cprintf (struct context* context, const char* fmt, ...) {
     return;
   }
 
+  memset (buf, 0, CPRINTF_BUF_MAX);
   int len = vsnprintf (buf, CPRINTF_BUF_MAX, fmt, args);
 
   va_end (args);