[min] Fix C++ style comment in C90 code

Author: mabl

src/Configuration/lwipopts.h

@@ -1028,7 +1028,7 @@
  *     LWIP_CALLBACK_API==1: The PCB callback function is called directly
  *         for the event.
  */
-//#define LWIP_EVENT_API
+/* #define LWIP_EVENT_API */
 
 /*
    ----------------------------------

src/Utilities/Stubs/stubs.h

@@ -8,7 +8,7 @@
 #ifndef STUBS_H_
 #define STUBS_H_
 
-///* The ABI requires a 64-bit type.  */
+/* The ABI requires a 64-bit type.  */
 __extension__ typedef int __guard __attribute__((mode (__DI__)));
 
 int __cxa_guard_acquire(__guard *);