tree be91ca20c94ed0bb8354a6cbd4fe0dd48a9e3d8a
parent 84436f791c2f76a82f56190ba9d744c904c07551
author Sergiu Deitsch <sergiu.deitsch@gmail.com> 1653608559 +0200
committer Sergiu Deitsch <sergiu.deitsch@gmail.com> 1705952579 +0100
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Use C++17 Bessel functions

Move Bessel functions availability checks from configuration time to
inclusion time to be more robust and allow the use of ABI compatible
compilers (e.g., Ceres is compiled using Clang but is used in a project
compiled using GCC.)

Since libc++ does not yet implement special math functions, we fallback
to their POSIX implementation if available. However, then only the
deprecated BesselJ{0,1,n} are provided.

Fixes #814

Change-Id: Ic3e62452b36e90cb22644cc8e553e3dd1881193f