Since the cysignals upgrade, running sage --gdb now gives

Program received signal SIGFPE, Arithmetic exception.

This is bad for several reasons:

1. Even though that SIGFPE is part of the normal flow of the program, people don't expect it and consider it a crash.

2. GDB halts at that point so Sage doesn't actually start.

3. Because of 2, it causes optional doctest failures when GDB is installed.

The newest release of cysignals avoids this problem by using a different mechanism to start up:

Tarball: https://pypi.python.org/packages/a5/c0/f07fbf4b4c5e6e77c8f1153a43a032f6cefb5c49d4180228fec051ee480b/cysignals-1.7.0.tar.gz

CC: @pjbruin

Component: user interface

Author: Jeroen Demeyer

Branch: 8b3a7c5

Reviewer: Peter Bruin

Issue created by migration from https://trac.sagemath.org/ticket/25092