[PROJ] proj_trans swaps X and Y?

[Matthew Woehlke]

I'm trying to convert between coordinate systems using 
proj_create_crs_to_crs and proj_trans.

In PROJ 4, coordinates are always in x,y,z (easting, northing, altitude) 
order. I just stuff my coordinates in and read them back, possibly with 
some conversion between degrees and radians, and everything Just Works.

If I try to do this in PROJ 5, it fails. As best as I can tell, lat-lon 
coordinate systems expect input, and provide output, as y, x, z.

Given that all I know is the EPSG, how do I determine the proper order 
in which to provide my inputs and read my outputs?

-- 
Matthew