Hello,

Guile musn't install its gmp custom allocator because it interfers with gnutls' use of gmp.
( see http://git.savannah.gnu.org/cgit/guile.git/commit/?id=b57bf2724a254cf73e255b3d2bca0a7dcad6674a )

Crashes can happen when freeing memory with an incorrect free memory function. Example:
 1- relay plugin is loaded
 2- ssl relay is created, gnutls allocates memory with its default allocator (malloc/free)
 3- guile plugin is loaded, guile register its custom gmp allocators (custom_gmp_malloc/custom_gmp_free)
 4- "/quit"
 5- relay plugin deinits gnutls -> gnutls deinits gmp -> gmp tries frees memory. Some memory allocated with malloc is passed to custom_gmp_free which is not correct => possible segfault

I've attached a simple patch to prevent guile from registering its gmp allocators.

Cheers,
Pierre Carru