horiz_interp_type_eq does not work with gnu

[uramirez8707]

Describe the bug
horiz_interp_type_eq does not work with gnu

This is because some of the members of the horiz_interp_type are allocatables

FMS/horiz_interp/horiz_interp_type.F90

Lines 118 to 127 in 77382e3

	integer, dimension(:,:), allocatable :: ilon !< indices for conservative scheme
	integer, dimension(:,:), allocatable :: jlat !< indices for conservative scheme
	!! wti ist used for derivative "weights" in bicubic
	integer, dimension(:,:,:), allocatable :: i_lon !< indices for bilinear interpolation
	!! and spherical regrid
	integer, dimension(:,:,:), allocatable :: j_lat !< indices for bilinear interpolation
	!! and spherical regrid
	logical, dimension(:,:), allocatable :: found_neighbors !< indicate whether destination grid
	!! has some source grid around it.
	integer, dimension(:,:), allocatable :: num_found

But some of the members are never allocatated, depending on the interpolation method. For example, ilon and jlat are never allocated if using bilinear.
https://github.com/NOAA-GFDL/FMS/blob/main/horiz_interp/include/horiz_interp_bilinear.inc

This causes error with GNU like

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

To Reproduce
The changes here can reproduce the issue
uramirez8707@05c78b4

Expected behavior
The subroutine should check if a variable is allocatable before attempting to copy it

System Environment
Describe the system environment, include:
I saw this using gcc/13.2.0 on the amd box, but it also happens in the CI

Additional context
Discover this while debugging #1556