loader: impl: add some libc/::std functions

Author: facchinm

cores/arduino/abi.cpp

@@ -12,10 +12,22 @@ extern "C" int __cxa_atexit(void (*func) (void *), void * arg, void * dso_handle
   (void)func; (void)arg; (void)dso_handle; // unused
   return 0;
 }
+extern "C" int atexit(void (*func)(void)) {
+  (void)func;
+  return 0;
+}
 
 namespace std {
-  [[gnu::weak, noreturn]] void terminate() {
-    abort();
+  void __throw_length_error(const char* __s __attribute__((unused))) {}
+  void __throw_bad_alloc() {}
+  void __throw_bad_function_call() {}
+};
+
+extern "C" int strcmp(const char* s1, const char* s2) {
+  while(*s1 && (*s1 == *s2))
+  {
+    s1++;
+    s2++;
   }
 }