properly skip leading spaces in Frame string

On aarch64 gdb does not start each frame with an address since it
can just follow the link register. Skipping characters up to the
first '0' is obviously incorrect in this case.

windows.cpp

@@ -2902,7 +2902,9 @@ void ThreadWindowUpdate(const char *, UIElement *_table) {
 		memcpy(thread.name, position, end - position);
 		thread.name[end - position] = 0;
 
-		position = strchr(end + 1, '0');
+		position = end + 1;
+		while (*position == ' ') position++;
+
 		end = strchr(position, '\n');
 		if (end - position >= (ptrdiff_t) sizeof(thread.frame))
 			end = position + sizeof(thread.frame) - 1;