devel/valgrind: patch for ifuncs

The work for simd support uses @gnu_indirect_function. When Valgrind sees
binaries using such function it expects to have its own ifunc_handler. Until now
there wasn't one for FreeBSD so Valgrind terminates with an abort.

This patch merges the fix maintainer and creator made upstream.

PR: 273955
Reported by: pjfloyd@wanadoo.fr (maintainer)