Init - do not register frame info w/ disabled exceptions

cores/esp8266/core_esp8266_main.cpp

@@ -279,16 +279,23 @@ static void loop_task(os_event_t *events) {
     ESP.setDramHeap();
 }
 
+#if __cpp_exceptions
 extern "C" {
 struct object { long placeholder[ 10 ]; };
 void __register_frame_info (const void *begin, struct object *ob);
 extern char __eh_frame[];
 }
 
-static void do_global_ctors(void) {
+static void do_register_frame_info() {
     static struct object ob;
     __register_frame_info( __eh_frame, &ob );
+}
+#else
+static void do_register_frame_info() {
+}
+#endif
 
+static void do_global_ctors(void) {
     void (**p)(void) = &__init_array_end;
     while (p != &__init_array_start)
         (*--p)();
@@ -322,6 +329,7 @@ void init_done() {
     system_set_os_print(1);
     gdb_init();
     std::set_terminate(__unhandled_exception_cpp);
+    do_register_frame_info();
     do_global_ctors();
     esp_schedule();
     ESP.setDramHeap();

cores/esp8266/libgcc_replacements.cpp

@@ -0,0 +1,31 @@
+/* replaces libgcc weak functions with stubs when exceptions are disabled
+ * ref. gcc-gnu/libgcc/crtstuff.c
+ *
+ * in case something calls them w/ -fno-exceptions
+ */
+
+#if !defined(__cpp_exceptions)
+#include <cstdlib>  // std::abort()
+#endif
+
+extern "C" {
+
+#if !defined(__cpp_exceptions)
+void __register_frame_info (const void*, struct object*) {
+    std::abort();
+}
+
+void __register_frame_info_bases (const void*, struct object*, void*, void*) {
+    std::abort();
+}
+
+void* __deregister_frame_info (const void*) {
+    std::abort();
+}
+
+void* __deregister_frame_info_bases (const void*) {
+    std::abort();
+}
+#endif
+
+}  // extern "C"