LibC: sys_errlist should be const char* const

Patch from Anonymous.

Libraries/LibC/errno.h

@@ -15,7 +15,7 @@
 
 __BEGIN_DECLS
 
-extern const char* sys_errlist[];
+extern const char* const sys_errlist[];
 extern int sys_nerr;
 extern __thread int errno;
 

Libraries/LibC/string.cpp

@@ -334,7 +334,7 @@ char* strncat(char* dest, const char* src, size_t n)
     return dest;
 }
 
-const char* sys_errlist[] = {
+const char* const sys_errlist[] = {
     "Success (not an error)",
     "Operation not permitted",
     "No such file or directory",