Fix build with GCC on FreeBSD

[pkubaj]

This is needed because some platforms still use GCC (like all powerpc platforms).

[rserban]

By the way, I don't think this is a GCC issue.
I suspect this is because of PATH_MAX?
While, in general, we prefer not to modify code in the "chrono_thirdparty" directory, I'm fine accepting this change. However, before that, could you please check if the following will work:

#ifdef __FreeBSD__
# include <limits.h>
#endif

[pkubaj]

Yes, this also works.

[rserban]

Could you then amend your PR? Or else I can push this fix.
Thanks

[pkubaj]

Changed.

[rserban]

I thought it's not worth pulling 2 commits for a single-line change, so I made and pushed this change directly. Please let me know if this works for you.

[pkubaj]

Yes, it works, thanks.