Re: [PATCH] Link to -lssp when available (fixes mingw build)

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 18 Dec 2019 12:14:13 -0600
> From: "Christian Biesinger via gdb-patches" <gdb-patches@sourceware.org>
> Cc: Christian Biesinger <cbiesinger@google.com>
> 
> Recent mingw versions require -lssp when using _FORTIFY_SOURCE, which
> gdb does (in common-defs.h)
> https://github.com/msys2/MINGW-packages/issues/5868#issuecomment-544107564
> 
> gdb/ChangeLog:
> 
> 2019-12-18  Christian Biesinger  <cbiesinger@google.com>
> 
> 	* configure: Regenerate.
> 	* gdbsupport/common.m4: Look for -lssp to fix mingw.

This will produce a GDB binary that requires libssp-0.dll to be
present to run, won't it?  And since libssp-0.dll is part of GCC,
this will have 2 annoying effects:

  . we could be in "DLL hell" if there's an incompatibility between
    libssp against which GDB was linkes and the one actually installed
    on the system where we run GDB;

  . if someone wants to distribute MinGW binaries of GDB, they will
    have to distribute the GCC sources as well, since DLLs cannot
    enjoy the libgcc-type exception

Is there a way to link against libssp.a statically?  If so, it would
be better to do that.  Failing that, I'd recommend not to define
_FORTIFY_SOURCE in MinGW builds, because the above annoyances IMO
outweigh its utility.

Thanks.