commit c8a1f887d7316f76853bd67ffe5a9bb556e54b57
Author: Raphael Kubo da Costa <rakuco@FreeBSD.org>
Date:   Fri Mar 25 17:48:33 2016 +0100

    nanoflann: Include <cstdlib> for ::malloc().

    malloc() is defined in stdlib.h, which was being included indirectly by
    other on Linux. On systems such as FreeBSD, the code was just failing to
    build because of the missing symbol.

--- vendor/nanoflann-1.1.8/nanoflann.hpp.orig	2015-11-25 18:45:33 UTC
+++ vendor/nanoflann-1.1.8/nanoflann.hpp
@@ -38,6 +38,7 @@
 #include <algorithm>
 #include <stdexcept>
 #include <cstdio>  // for fwrite()
+#include <cstdlib> // for malloc()
 #include <cmath>   // for fabs(),...
 #include <limits>