syscalls: Provide nop stubs to avoid libgcc unwinder

src/platforms/common/syscalls.c

@@ -186,3 +186,16 @@ __attribute__((used)) void *_sbrk(const ptrdiff_t alloc_size)
 	heap_current += alloc_size;
 	return result;
 }
+
+/* ARM EABI Personality functions for newlib-4.3.0 */
+__attribute__((weak)) void __aeabi_unwind_cpp_pr0()
+{
+}
+
+__attribute__((weak)) void __aeabi_unwind_cpp_pr1()
+{
+}
+
+__attribute__((weak)) void __aeabi_unwind_cpp_pr2()
+{
+}