proj4 needs to be updated to proj v9 and make to work with the github version of wgrib2

[edwardhartnett]

Right now we have a cmake option:

option(USE_PROJ4 "Use Proj4?" off)
And there is code that uses USE_PROJ4 in ifdefs:

#include <stdio.h>
#include <stdlib.h>

#include "grb2.h"
#include "wgrib2.h"
#include "fnlist.h"

#ifdef USE_PROJ4

#include "proj_api.h"
#include "proj4_wgrib2.h"

int proj4_initialize(unsigned char **sec, struct proj4_struct *projection) {

    unsigned int gdt;
    unsigned char *gds;
    int has_np, center;

(proj4_initialize.c)

But there is nothing in the makefile to find and link to the proj4 library.

[edwardhartnett]

proj4 was a development tool for testing purposes.

Then someone found a grid which needed proj4, so for a few versions of wgrib2, proj4 became a default on option (this was after the first cmake build done by Kyle).

As far as we know this is only used by UK Met office.