Looks like HAVE_SIGINFO_H is useless since the following patch
that removed ./src/c_compat.c :
patch 0a0f1a0fceb9c567475e9681e8c1e90a6907db99
Author: Ganesh Sittampalam <ganesh@earth.li>
Date: Tue Nov 24 16:01:45 ART 2009
* drop a bunch of old C helper code
2 patches for repository http://darcs.net:
patch 6b24ae60d8aea1c3a7608197fc3b5a0238bff2a5
Author: Guillaume Hoffmann <guillaumh@gmail.com>
Date: Wed Feb 3 08:08:33 ART 2016
* drop definition of HAVE_SIGINFO_H unused since 2009
patch 4d3a8c62ea53e4fbec095080918c0737f60eb4a9
Author: Guillaume Hoffmann <guillaumh@gmail.com>
Date: Wed Feb 3 08:46:12 ART 2016
* comment use of flag REENTRANT